Change admin account will locked for a minimum of 30 minutes

after i tried some failue tests to login to my admin, i get this:

Important Notice: There have been multiple unsuccessful login attempts to your administrative account. For your protection and for system security, after 6 attempts the account will be locked for a minimum of 30 minutes, during which you will be unable to login even if you remember your password. Continued attempts to login will continue to lock the account for another 30 minutes. You will not be able to do password resets during this time. Apologies for the inconvenience.

now i want to change the 30 minutes to 1 second, cause i need do some more tests.
i would change it back to 30 minutes after i finish the tests.

but i don't know what do i change this "30 minutes" ?

Look in \YOUR_ADMIN\login.php:
Line 12: define('ADMIN_LOGIN_LOCKOUT_TIMER', (30 * 60));

Change the number (in seconds) to change the interval.