innodb MySQL5.7版
大家好，正如标题所说，我在mysql工作台上使用的查询超时了。我使用的查询和一周前一样，但是不是0.5秒，而是15-25秒。。示例如下：

SELECT * FROM <table> ORDER BY <time column> DESC;

另一方面，我正在使用一些相当长的mysql查询，以便从数据中收集一些粗略的统计数据，我预计这些查询需要更长的时间，但我不确定是否有更好的方法来完成。我还应该提到，我目前只有 SELECT/SHOW 权限。。下面是超时的较长查询：

SELECT DATE(<time_sent_column>) as Update_Date, 
ABS(AVG(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>))) AS AVG_Latency,
AVG((SELECT 
    ABS(AVG(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>))) 
    FROM <table_name> 
    WHERE ((UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>) < 10800))))
AS Total_Average_Latency,
STDDEV(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>)) as STDDEV_Latency,
AVG((SELECT 
    ABS(STDDEV(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>))) 
    FROM <table_name> 
    WHERE ((UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>) < 10800))))
AS Total_STDDEV_Latency,
VAR_SAMP(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(create_date)) as Variance_Latency,
AVG((SELECT 
    ABS(VAR_SAMP(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>))) 
    FROM <table_name>
    WHERE ((UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>) < 10800))))
AS Average_Variance_Latency,
MIN(ABS((UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>)))) AS Min_Latency,
MAX(ABS((UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>)))) AS Max_Latency
FROM <table_name>
WHERE ((ABS(UNIX_TIMESTAMP(<time_created_column>) - UNIX_TIMESTAMP(<time_sent_column>)) < 10800) AND created_at > '2018-05-01')
GROUP BY DATE(<time_created_column>)
ORDER BY DATE(<time_created_column>) DESC;

我可以分解所有这些，但是如果可能的话，我更希望在查询之后将它们放在一个表中。。我是mysql的新手，所以我不确定我是否能使用它 JOINs 或是那种只有 SELECT/SHOW 权限。。
数据库有50%的连接，最小流量，98.7%的密钥效率，87.5%的innodb缓冲区使用率，每秒0次读/写。。任何建议都太好了！谢谢！