There is no key, correct.
There is a USB C access point for emergency power that once applied will allow you to unlock the door.
Minus one battery, using the Wyze Car Power Bank to unlock Wyze Bolt Lock
Using cell phone to unlock with one battery out (did this with an iPhone 12 Max Pro and Pixel 6 both worked)
Note, to use the cell phone method, you have to plug your cable into the cell phone first, then plug into the Wyze Bolt keypad second.