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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 (
    8373, 8374, 8375, 8376, 8377, 8379, 8387, 
    8388, 8389, 8391, 8392, 8394, 8396, 
    8399, 8403, 8404
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "ALL",
      "possible_keys": ["PRIMARY"],
      "rows": 5,
      "filtered": 100,
      "attached_condition": "cscart_product_review_prepared_data.storefront_id = 0 and cscart_product_review_prepared_data.product_id in (8373,8374,8375,8376,8377,8379,8387,8388,8389,8391,8392,8394,8396,8399,8403,8404)"
    }
  }
}