如何使用多列索引优化 MySQL 查询

我对MySQL索引很陌生。我正在尝试为web_products表创建索引。我创建了索引IsDataActive_IsVerified_IsExpired_Price_Sale来优化以下查询;

SELECT 
MAX(Price_Sale) as maxColumn
FROM
`web_products` `t`
WHERE
IsDataActive = 1 AND IsVerified = 1
    AND IsExpired = 0

当我使用Explain分析查询时，我得到了最好的结果"Select tables optimized away".

我还有另一个查询，性能很差。web_products表可能包含数百万种产品。执行以下查询需要几分钟时间;

SELECT 
COUNT(P.BrandID)
FROM
web_products AS P
WHERE
P.OriginalItemID IS NULL
    AND P.IsDataActive = 1
    AND P.IsExpired = 0
    AND P.IsVerified = 1;

BrandID是 FK 到brands表。以下是上述查询的解释分析。如何优化上述查询？

更新 1

答案中提到的Index对于上述查询非常有效。我能够在不到 0.200 毫秒的时间内获得结果。

我已经修改了第二个查询并将MerchantID添加到索引中，现在执行以下查询需要 1 秒。说明显示rows examined的数量88331。有没有办法将执行时间提高到毫秒？

SELECT 
P.BrandID, COUNT(P.BrandID) as Count, B.Name
FROM
web_products AS P
    inner join
web_brands as B ON P.BrandID = B.ID
    INNER JOIN
web_merchants M ON P.MerchantID = M.ID
    LEFT JOIN
web_products_features F ON P.ID = F.Product_ID
WHERE
P.OriginalItemID IS NULL
    AND P.IsDataActive = 1
    AND P.IsExpired = 0
    AND P.IsVerified = 1
    AND B.IsDataActive = 1
group by P.BrandID
order by Count desc
Limit 100