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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 (12, 78, 79, 11, 41, 28, 7, 27) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00023

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_product_review_prepared_data	range	PRIMARY	PRIMARY	7		8	Using index condition

Result

product_id	average_rating	reviews_count
41	1.00	1
78	4.00	1