SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    36310, 36332, 36333, 36334, 36335, 36336, 
    36337, 36338, 36331, 36330, 36329, 
    36328, 36327, 36326, 36325, 36324, 
    36323, 36322, 36321, 36320, 36319, 
    36318, 36317, 36316
  ) 
  AND feature_id IN (23690, 23691) 
  AND lang_code = 'vi'

Query time 0.00837

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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",
          "key_length": "12",
          "used_key_parts": ["product_id", "feature_id", "lang_code"],
          "rows": 48,
          "filtered": 100,
          "attached_condition": "cscart_product_features_values.product_id in (36310,36332,36333,36334,36335,36336,36337,36338,36331,36330,36329,36328,36327,36326,36325,36324,36323,36322,36321,36320,36319,36318,36317,36316) and cscart_product_features_values.feature_id in (23690,23691) and cscart_product_features_values.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}