SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    12725, 12726, 12727, 12728, 12729, 12730, 
    12731, 12732, 12733, 12734, 12735, 
    12736, 12737, 12738, 12739, 12740, 
    12741, 12742, 12743, 12724, 12723, 
    12722, 12721, 12720, 12719, 12718, 
    12717, 12716, 12715, 12714
  ) 
  AND feature_id IN (553, 625, 624, 627, 628) 
  AND lang_code = 'en'

Query time 0.00528

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.28"
    },
    "table": {
      "table_name": "cscart_product_features_values",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "fl",
        "lang_code",
        "product_id",
        "fpl",
        "idx_product_feature_variant_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "key_length": "15",
      "rows_examined_per_scan": 29,
      "rows_produced_per_join": 29,
      "filtered": "100.00",
      "using_index_for_skip_scan": true,
      "cost_info": {
        "read_cost": "7.38",
        "eval_cost": "2.90",
        "prefix_cost": "10.28",
        "data_read_per_join": "22K"
      },
      "used_columns": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "attached_condition": "((`test2_gaseus`.`cscart_product_features_values`.`product_id` in (12725,12726,12727,12728,12729,12730,12731,12732,12733,12734,12735,12736,12737,12738,12739,12740,12741,12742,12743,12724,12723,12722,12721,12720,12719,12718,12717,12716,12715,12714)) and (`test2_gaseus`.`cscart_product_features_values`.`feature_id` in (553,625,624,627,628)) and (`test2_gaseus`.`cscart_product_features_values`.`lang_code` = 'en'))"
    }
  }
}