Mysqd load 100% in CPU. How fix it?

Hi,

I cant understand why select in db load cpu in 100%/ this is problem.

This sql cant load db

$sql = "SELECT
device,
battery,
timestamp,
events,
(select count(id) from deviceevents as de where de.device = deviceevents.device and de.events LIKE '%kill app%') as countInstalls,
temperature
FROM deviceevents
where id in (SELECT max(id) FROM `deviceevents` group by device) ORDER BY timestamp ASC";

root@screenlog:~# top

top - 11:21:08 up 3 days, 2:44, 1 user, load average: 4.73, 4.08, 2.43 Tasks: 78 total, 2 running, 76 sleeping, 0 stopped, 0 zombie %Cpu(s): 99.7 us, 0.3 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 1017872 total, 945804 used, 72068 free, 96220 buffers KiB Swap: 102396 total, 0 used, 102396 free. 658612 cached Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 8874 mysql 20 0 892308 68756 7632 S 99.7 6.8 34:39.57 mysqld 23871 root 20 0 24932 1588 1116 R 0.3 0.2 0:00.04 top 1 root 20 0 33476 2800 1440 S 0.0 0.3 0:04.11 init