SELECT 
  pf.feature_id, 
  pf.company_id, 
  pf.feature_type, 
  pf.parent_id, 
  pf.display_on_product, 
  pf.display_on_catalog, 
  pf.display_on_header, 
  pf.categories_path, 
  pf.status, 
  pf.comparison, 
  pf.position, 
  pf.purpose, 
  pf.feature_style, 
  pf.filter_style, 
  pf.feature_code, 
  pfd.description, 
  pfd.lang_code, 
  pfd.prefix, 
  pfd.suffix, 
  pfd.full_description, 
  pfv.value, 
  pfv.variant_id, 
  pfv.value_int, 
  pfv.product_id 
FROM 
  cscart_product_features_values AS pfv 
  LEFT JOIN cscart_product_features AS pf ON pfv.feature_id = pf.feature_id 
  LEFT JOIN cscart_product_features_descriptions AS pfd ON pfd.feature_id = pf.feature_id 
  AND pfd.lang_code = 'en' 
WHERE 
  1 = 1 
  AND pfv.product_id IN (
    12348, 12347, 12346, 12345, 12344, 12343, 
    12342, 12341, 12340, 12339, 12338, 
    12337, 12336, 12335, 12334, 12333, 
    12332, 12331, 12330, 12329, 12328, 
    12327, 12326, 12325, 12324, 12323, 
    12322, 12321, 12320, 12319, 12318, 
    12317, 12316, 12315, 12314, 12313, 
    12312, 12311, 12310, 12309, 12308, 
    12307, 12306, 12305, 12304, 12303, 
    12302, 12301, 12300, 12299, 12298, 
    12297, 12296, 12295, 12294, 12293, 
    12292, 12291, 12290, 12289, 12288, 
    12287, 12286, 12285, 12284, 12283, 
    12282, 12281, 12280, 12279, 12278, 
    12277, 12276, 12275, 12274, 12273, 
    12272, 12271, 12270, 12269, 12268, 
    12267, 12266, 12265, 12264, 12263, 
    12262, 12261, 12260, 12259
  ) 
  AND pfv.lang_code = 'en' 
  AND pf.feature_code IN ('Brand', 'ISBN', 'GTIN', 'MPN')

Query time 0.01162

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "2393.22"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 3307,
          "rows_produced_per_join": 1801,
          "filtered": "54.46",
          "index_condition": "((`test2_gaseus`.`pfv`.`product_id` in (12348,12347,12346,12345,12344,12343,12342,12341,12340,12339,12338,12337,12336,12335,12334,12333,12332,12331,12330,12329,12328,12327,12326,12325,12324,12323,12322,12321,12320,12319,12318,12317,12316,12315,12314,12313,12312,12311,12310,12309,12308,12307,12306,12305,12304,12303,12302,12301,12300,12299,12298,12297,12296,12295,12294,12293,12292,12291,12290,12289,12288,12287,12286,12285,12284,12283,12282,12281,12280,12279,12278,12277,12276,12275,12274,12273,12272,12271,12270,12269,12268,12267,12266,12265,12264,12263,12262,12261,12260,12259)) and (`test2_gaseus`.`pfv`.`lang_code` = 'en'))",
          "cost_info": {
            "read_cost": "1330.55",
            "eval_cost": "180.11",
            "prefix_cost": "1510.66",
            "data_read_per_join": "1M"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id",
            "value",
            "value_int",
            "lang_code"
          ]
        }
      },
      {
        "table": {
          "table_name": "pf",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "test2_gaseus.pfv.feature_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 720,
          "filtered": "40.00",
          "cost_info": {
            "read_cost": "450.29",
            "eval_cost": "72.05",
            "prefix_cost": "2141.06",
            "data_read_per_join": "849K"
          },
          "used_columns": [
            "feature_id",
            "feature_code",
            "company_id",
            "purpose",
            "feature_style",
            "filter_style",
            "feature_type",
            "categories_path",
            "parent_id",
            "display_on_product",
            "display_on_catalog",
            "display_on_header",
            "status",
            "position",
            "comparison"
          ],
          "attached_condition": "(`test2_gaseus`.`pf`.`feature_code` in ('Brand','ISBN','GTIN','MPN'))"
        }
      },
      {
        "table": {
          "table_name": "pfd",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "test2_gaseus.pfv.feature_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 720,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "180.11",
            "eval_cost": "72.05",
            "prefix_cost": "2393.22",
            "data_read_per_join": "1M"
          },
          "used_columns": [
            "feature_id",
            "description",
            "full_description",
            "prefix",
            "suffix",
            "lang_code"
          ]
        }
      }
    ]
  }
}