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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 (
    21583, 21584, 21585, 21586, 21587, 21588, 
    21589, 21590, 21591, 21592, 21593, 
    21594, 21595, 21596, 21597, 21598
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00018

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 (21583,21584,21585,21586,21587,21588,21589,21590,21591,21592,21593,21594,21595,21596,21597,21598)"
    }
  }
}