Filters the return value of check_password_reset_key() when an old-style key is used. 

Parameters

Previously

( 3.7.0 ) plain-text keys were stored in the database. . . .

Previously

( 4.3.0 ) key hashes were stored without an expiration time. . . .

$return

( WP_Error ) A WP_Error object denoting an expired key. Return a WP_User object to validate the key. . . .

( int ) $user_id The matched user ID. . . .