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SELECT 
  cscart_ult_product_descriptions.product_id, 
  cscart_ult_product_descriptions.short_description, 
  IF(
    cscart_ult_product_descriptions.short_description = "", 
    cscart_ult_product_descriptions.full_description, 
    ""
  ) AS full_description, 
  cscart_ult_product_descriptions.meta_keywords, 
  cscart_ult_product_descriptions.meta_description, 
  cscart_ult_product_descriptions.search_words, 
  cscart_ult_product_descriptions.promo_text 
FROM 
  cscart_ult_product_descriptions 
WHERE 
  cscart_ult_product_descriptions.product_id IN (
    20971, 19878, 19896, 19908, 20576, 19871, 
    19885, 20972, 19905, 19897, 19909, 
    20955, 19872, 21078, 19886, 20973, 
    19820, 19898, 19910, 20956, 19873, 
    18661, 20974, 19860, 19899, 19911, 
    20957, 19874, 18662, 19889, 21923, 
    19863, 19900, 20154, 20958, 19875, 
    20088, 19890, 21924, 19865, 19901, 
    20959, 19876, 20089, 19925, 19891, 
    21102, 19866, 19902, 20724, 21925, 
    19877, 20091, 19883, 19892, 21103, 
    19867, 19903, 20725, 21926, 19880, 
    20092, 20087, 19893, 19868, 19904, 
    22277, 19881, 20093, 19888, 19894, 
    18664, 19869, 19906, 19882, 20094, 
    19879, 19895, 19131, 19870, 19907, 
    20728, 19884, 20065, 19887, 20723, 
    21749, 20726, 20727
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'ru'

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}