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 (
    69998, 66980, 27362, 9551, 26143, 37312, 
    65082, 38874
  ) 
  AND cscart_product_review_prepared_data.storefront_id = 0

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.97"
    },
    "table": {
      "table_name": "cscart_product_review_prepared_data",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "storefront_id"
      ],
      "key_length": "7",
      "rows_examined_per_scan": 8,
      "rows_produced_per_join": 8,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "3.17",
        "eval_cost": "0.80",
        "prefix_cost": "3.97",
        "data_read_per_join": "128"
      },
      "used_columns": [
        "product_id",
        "storefront_id",
        "average_rating",
        "reviews_count"
      ],
      "attached_condition": "((`cscart_db`.`cscart_product_review_prepared_data`.`storefront_id` = 0) and (`cscart_db`.`cscart_product_review_prepared_data`.`product_id` in (69998,66980,27362,9551,26143,37312,65082,38874)))"
    }
  }
}

Result

product_id average_rating reviews_count
9551 5.00 5
26143 5.00 2
37312 5.00 2
69998 4.88 8