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SELECT 
  cscart_product_review_prepared_data.product_id AS product_id, 
  cscart_product_review_prepared_data.average_rating AS average_rating, 
  cscart_product_review_prepared_data.reviews_count AS reviews_count 
FROM 
  cscart_product_review_prepared_data 
WHERE 
  cscart_product_review_prepared_data.product_id IN (
    6947, 3424, 3911, 3422, 3910, 3421, 3909, 
    3420, 3423, 3912, 3135, 3403
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00022

JSON explain

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