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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 (
    2496, 2957, 2838, 836, 2958, 1943, 2959, 
    2960, 1945, 2137, 847, 835, 848, 2965, 
    2966, 2967, 2968, 2969, 2970, 2971
  ) 
  AND cscart_ult_product_descriptions.company_id = 1 
  AND cscart_ult_product_descriptions.lang_code = 'ru'

Query time 0.00045

JSON explain

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