SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    12653, 12652, 12651, 12650, 12649, 12648, 
    12647, 12646, 12645, 12644, 12643, 
    12642, 12641, 12640, 12639, 12624, 
    12625, 12626, 12627, 12628, 12629, 
    12630, 12631, 12632, 12633, 12634, 
    12635, 12636, 12637, 12638
  ) 
  AND feature_id IN (553, 625, 624, 627, 628) 
  AND lang_code = 'en'

Query time 0.00321

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.55"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "using_index_for_skip_scan": true,
      "cost_info": {
        "read_cost": "7.55",
        "eval_cost": "3.00",
        "prefix_cost": "10.55",
        "data_read_per_join": "23K"
      },
      "used_columns": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "attached_condition": "((`test2_gaseus`.`cscart_product_features_values`.`product_id` in (12653,12652,12651,12650,12649,12648,12647,12646,12645,12644,12643,12642,12641,12640,12639,12624,12625,12626,12627,12628,12629,12630,12631,12632,12633,12634,12635,12636,12637,12638)) 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'))"
    }
  }
}