Mysql 关联查询的问题

在写业务时，遇到查询，因为数据量增大，导致查询时间冲着 5s 去了，想了一天也不知道该怎么优化，来求各位大佬支个招。

（1）三张表，每张表都有 5000 条左右的数据。

（2）consume 是主表，分别和 org 表和 admin 表有“一对多”关系。

（3）现需要对三张表进行联合查询，查询结果去重排序。

最开始使用的语句是，时间超过 10s 了：

SELECT * FROM consume WHERE uid IN (
             SELECT c.uid FROM consume AS c
              LEFT JOIN consume_admin AS a ON c.uid=a.consume_id AND a.deleted=0 
              LEFT JOIN consume_org AS o ON o.consume_id=c.uid AND o.deleted=0
              WHERE c.deleted=0 and a.deleted=0 and o.deleted=0 AND (a.user_id='126949' OR c.create_user_id='126949')) order by create_at desc;

然后百度了一下，稍微改进了一下，但还是不如意：

select c.* FROM consume AS c
              LEFT JOIN consume_admin AS a ON c.uid=a.consume_id AND a.deleted=0 
              LEFT JOIN consume_org AS o ON o.consume_id=c.uid AND o.deleted=0
							WHERE c.deleted=0 and a.deleted=0 and o.deleted=0 AND (a.user_id='126949' OR c.create_user_id='126949') group by c.uid order by c.create_at desc;

求各位大佬帮帮忙了！！

PS：发现把 admin 表和 org 表单独查一次，然后取到的 consume_id 再到 consume 表里用 uid IN 查询会更快，但是我看百度里说都是直接联表查询比这种分步的快，是我写的 sql 太差了么。