mysql doing very strange things

Hi,
I have a couple of wordpress sites running on some load balanced hosts: 1 load balancing machine, two web servers, and a database machine. However, other than on cached pages, my sites perform extremely slowly. For example sometimes it will take as long as 10 or 15 seconds to load the admin interface on some of my sites. I don’t believe it is the web server’s fault, because the cached pages return quite quickly.
Now, however, I’m having a problem pinning down what it could be. I’ve run mysql slow query logs, and sometimes queries from the options table (and sometimes others) takes up to 29 or more seconds to complete, and this is in a table with probably no more than 200 rows. Obviously this is ridiculous, but this is what’s happening. I ran sysbench on my mysql server to see if it could be doing something wrong, and it came back with an average of 256 or so transactions per second, which does not show anything of the 29 second transactions I’ve been seeing. I’ve also checked memory and cpu, and both seem fine. Disk also seems fine.
Now my question: Is there anything else I can do to figure out why these queries are taking so ridiculously long?
Thanks,
-Michael.

Sites: https://michaeltaboada.me, https://2mb.solutions.