One way to monitor DB activity in MySQL is to enable logging and then tail the log file.
mysql -u root -p
You can check the status of logging and get the path of the log file with:
SHOW VARIABLES LIKE "general_log%";
And then enable logging with:
SET GLOBAL general_log = 'ON';
Finally, tail the log:
tail -f /usr/local/var/mysql/MUSPB250049-419.log