Do MySQL can do automatic EXPLAIN on every query?
Enable MySQL's Slow Query log.
Anything that takes more than the defined time will get written into that log and you can take a look at it.
Or, better still, throw it back at the Developer that wrote the query and get them to take a look at it and then then write a better query.
&quot;Teach a man to fish ...&quot; and all that ...
Databases are everybody's responsibility, not just the DBA's.