Locked out of CiviCRM admin
The easiest way would probably be to override this value in civicrm.settings.php.
There should be a commented out line something like:

// $civicrm_setting['URL Preferences']['userFrameworkResourceURL'] = '....';


You can uncomment this line by removing the leading '//' and edit the url. 
Make a backup of civicrm.settings.php first.

If you wanted to make a change in the database you can do this by editing the value of civicrm_setting for the row with name "userFrameworkResourceURL".

I'd recommend backing up the database or at least that table first.

If you have logging enabled via (Admin -> System Settings ->  Misc (Undelete, PDFs, Limits, Logging, Captcha, etc.) ) 

You could find the previous value for this in the log_civicrm_setting table.