SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    11071, 11088, 11087, 11086, 11085, 11084, 
    11083, 11082, 11081, 11080, 11079, 
    11078, 11077, 11076, 11067, 11068, 
    11072, 11074, 11069, 11070, 11073, 
    11075
  ) 
  AND feature_id IN (553, 624, 623) 
  AND lang_code = 'en'

Query time 0.00334

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18.27"
    },
    "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": "idx_product_feature_variant_id",
      "used_key_parts": [
        "product_id",
        "feature_id",
        "lang_code"
      ],
      "key_length": "12",
      "rows_examined_per_scan": 79,
      "rows_produced_per_join": 79,
      "filtered": "100.00",
      "using_index": true,
      "cost_info": {
        "read_cost": "10.38",
        "eval_cost": "7.90",
        "prefix_cost": "18.28",
        "data_read_per_join": "61K"
      },
      "used_columns": [
        "feature_id",
        "product_id",
        "variant_id",
        "lang_code"
      ],
      "attached_condition": "((`gaseus`.`cscart_product_features_values`.`product_id` in (11071,11088,11087,11086,11085,11084,11083,11082,11081,11080,11079,11078,11077,11076,11067,11068,11072,11074,11069,11070,11073,11075)) and (`gaseus`.`cscart_product_features_values`.`feature_id` in (553,624,623)) and (`gaseus`.`cscart_product_features_values`.`lang_code` = 'en'))"
    }
  }
}