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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 (
    8906, 8908, 8909, 8914, 8915, 8919, 8920, 
    8921, 8924, 8927, 8929, 8930, 8932, 
    8934, 8935, 8936
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00017

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 (8906,8908,8909,8914,8915,8919,8920,8921,8924,8927,8929,8930,8932,8934,8935,8936)"
    }
  }
}