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 (
    2321, 2859, 1708, 631, 626, 632, 627, 
    633, 2442, 766, 1891, 1932, 2426, 2427, 
    1933, 1883, 1882, 2428, 726, 727
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "2.01"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "ALL",
      "possible_keys": [
        "PRIMARY"
      ],
      "rows_examined_per_scan": 15,
      "rows_produced_per_join": 15,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "0.51",
        "eval_cost": "1.50",
        "prefix_cost": "2.01",
        "data_read_per_join": "240"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`zdrowy_db`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`zdrowy_db`.`cscart_product_review_prepared_data`.`product_id` in (2321,2859,1708,631,626,632,627,633,2442,766,1891,1932,2426,2427,1933,1883,1882,2428,726,727)))"
    }
  }
}