SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    12775, 12776, 12777, 12778, 12779, 12780, 
    12781, 12753, 12754, 12755, 12756, 
    12757, 12758, 12759, 12760, 12761, 
    12762, 12763, 12764, 12765, 12766, 
    12767, 12768, 12769, 12770, 12771, 
    12772, 12773, 12774, 12752
  ) 
  AND feature_id IN (553, 625, 624, 627, 628) 
  AND lang_code = 'en'

Query time 0.00383

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 (12775,12776,12777,12778,12779,12780,12781,12753,12754,12755,12756,12757,12758,12759,12760,12761,12762,12763,12764,12765,12766,12767,12768,12769,12770,12771,12772,12773,12774,12752)) 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'))"
    }
  }
}