Can I increase/decrease the time users have to wait before the link expires?

As of version 1.5.2 you can now set your own time limit in minutes that a unique link will expire.

To do this, edit your wp-config.php file and add the following:

define('SS88_2FAVE_LINK_EXPIRES_MINUTES', 10);

Where the number 10 is, change this to whatever value (in minutes) you prefer.

By default if no value is set, the unique login link will expire after 15 minutes.