How to get number of locks acquired by my MySQL Query?
As per info linked in comment - it needs some preparing, cannot probably be used automatically:
that is output from

show engine innodb status


You can see it if you do in commandline:

begin;
update employees set store_id = 0 where store_id = 1;


and then in any (even the same) session

show engine innodb status\G


Where you look for section labeled

------------
TRANSACTIONS
------------


and find transaction which the update is part of.

Original answer (still holds for general usage IMHO)
I don't think it is possible directly, but you can get some details about locks from server status:

show session status like 'Innodb_%_lock%';


if you run it before and after query, you can check difference and analyze it.