SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    26893, 32726, 32727, 32728, 32729, 32730, 
    32731, 32732, 32733, 32734, 32735, 
    32736
  ) 
  AND feature_id IN (23358, 23350) 
  AND lang_code = 'vi'

Query time 0.00804

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": 24,
          "filtered": 100,
          "attached_condition": "cscart_product_features_values.product_id in (26893,32726,32727,32728,32729,32730,32731,32732,32733,32734,32735,32736) and cscart_product_features_values.feature_id in (23358,23350) and cscart_product_features_values.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}