To get Current timezone of the mysql you can do following things:
SELECT @@system_time_zone; # from this you can get the system timezone
SELECT IF(@@session.time_zone = 'SYSTEM', @@system_time_zone, @@session.time_zone) # This will give you time zone if system timezone is different from global timezone
Now if you want to change the mysql timezone then:
SET GLOBAL time_zone = '+00:00'; # this will set mysql timezone in UTC
SET @@session.time_zone = "+00:00"; # by this you can chnage the timezone only for your particular session