To unlock a blocked the user before the blocking threshold has elapsed, the database admin needs to connect to the identity config database(which is usually named idconfigdb, where and are configured at the time of installation), and issue the following SQL (sample SQL below for MySQL):
set sql_safe_updates = 0;
UPDATE users
SET
user_status = 'active',
login_fail_count = 0
WHERE
userid = '<the blocked userid here>';
set sql_safe_updates = 1;