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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 (
    6534, 6615, 6616, 6617, 6618, 6619, 6620, 
    6621, 6622, 2272, 2273, 2274, 2275, 
    2276, 2340, 2341, 2342, 2343, 2344, 
    2345, 2346, 2347, 2348, 2421
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00020

JSON explain

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