SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    325721, 21545, 18228, 163607, 164330, 
    169528, 175066, 184043, 191208, 216438, 
    263004, 279659, 295751, 307166, 308366, 
    315969, 315971, 317489, 317495, 317523, 
    317945, 321995, 321998, 324572
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00110

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "109K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text",
        "unit_name"
      ],
      "attached_condition": "((`unicomps`.`cscart_product_descriptions`.`product_id` in (325721,21545,18228,163607,164330,169528,175066,184043,191208,216438,263004,279659,295751,307166,308366,315969,315971,317489,317495,317523,317945,321995,321998,324572)) and (`unicomps`.`cscart_product_descriptions`.`lang_code` = 'ru'))"
    }
  }
}