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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    8725, 8522, 7507, 7510, 7508, 7905, 7906, 
    7511, 7968, 7527, 8722, 7966, 7908, 
    7514, 7963, 8582, 8530, 7901, 7566, 
    7907, 7593, 7902, 7806, 7956, 7957, 
    7929, 7924
  ) 
  AND cscart_product_descriptions.lang_code = 'ru'

Query time 0.00059

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "18.91"
    },
    "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": 27,
      "rows_produced_per_join": 27,
      "filtered": "100.00",
      "index_condition": "((`primapearl_r_new`.`cscart_product_descriptions`.`product_id` in (8725,8522,7507,7510,7508,7905,7906,7511,7968,7527,8722,7966,7908,7514,7963,8582,8530,7901,7566,7907,7593,7902,7806,7956,7957,7929,7924)) and (`primapearl_r_new`.`cscart_product_descriptions`.`lang_code` = 'ru'))",
      "cost_info": {
        "read_cost": "16.21",
        "eval_cost": "2.70",
        "prefix_cost": "18.91",
        "data_read_per_join": "102K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text"
      ]
    }
  }
}