What methods can reduce JDBC thread pauses?

What methods can reduce JDBC thread pauses?

We are running a Java server application which needs to fetch information
from a MySQL database in order to display data to the connected client.
However, due to the many clients connected at a single time, it has to
perform many queries in a short amount of time.
As a result of this, there is major lag/delay and threads will deadlock
and pause until the query is complete...
Are there any methods that we can use to prevent the thread from locking
up whilst waiting for the database apart from making it async, because we
need the data in sync?
I've seen things such as connection pooling however we need a way to fetch
data from the database in sync, without making the rest of the server
application lag.
It should be when a user hits x, y will happen instead of user hits x, the
program locks up and pauses for 2 seconds then y will happen once
complete.