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 (
    19501, 19502, 19503, 19504, 19505, 19506, 
    19507, 19508, 19509, 19510, 19511, 
    19512, 19513, 19514, 19515, 19516
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00020

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 (19501,19502,19503,19504,19505,19506,19507,19508,19509,19510,19511,19512,19513,19514,19515,19516)"
    }
  }
}