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 (
    388826, 388827, 388828, 388829, 388830, 
    388831, 388833, 388834, 388835, 388837, 
    388838, 388839, 388840, 388841, 388844, 
    388845, 388847, 388848, 388849, 388850
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "5.87"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "ALL",
      "possible_keys": [
        "PRIMARY"
      ],
      "rows_examined_per_scan": 19,
      "rows_produced_per_join": 19,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "2.07",
        "eval_cost": "3.80",
        "prefix_cost": "5.87",
        "data_read_per_join": "304"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`webmarco`.`cscart_product_review_prepared_data`.`product_id` in (388826,388827,388828,388829,388830,388831,388833,388834,388835,388837,388838,388839,388840,388841,388844,388845,388847,388848,388849,388850)))"
    }
  }
}