php and mysql date time difference -

i did in php store lastlogin in mysql datetime column

date('y-m-d h:i:s') //which gave > '2014-01-04 08:00:56' 

and saved it

when need calculate users have been online more 20 minutes, did in mysql

select * `elc_users`  timestampdiff( minute , lastlogin, now( ) ) <20 

it didn't work, when traced in mysql, now() gave > 2014-01-04 20:00:56

now wont let me 20 minutes logged in users.

how can fix this?

edit

i inserted record manually in phpmyadmin, sure whthear timezone issue in timestamp column default value current_timestamp, gave 2014-01-05 06:48:21. ran query in phpmyadmin

select created, now( )  `elc_users` 

this gave 2014-01-05 18:53:53

now exec code below check global , session timezone, , got phpmyadmin

mysql> select @@global.time_zone, @@session.time_zone; 

which gave system | system

like filip said it's timezone issue; can change timezone of script whatever timezone mysql set this:

date_default_timezone_set('america/los_angeles');