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 (
    255961, 255970, 260992, 261904, 285179, 
    285196, 295915, 315813, 141322, 163581, 
    183619, 210845, 223011, 225199, 236271, 
    238472, 253367, 285186, 285188, 295887, 
    308293, 308343, 308345, 317513
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00075

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 (255961,255970,260992,261904,285179,285196,295915,315813,141322,163581,183619,210845,223011,225199,236271,238472,253367,285186,285188,295887,308293,308343,308345,317513)) and (`unicomps`.`cscart_product_descriptions`.`lang_code` = 'ru'))"
    }
  }
}