Your key fob has an emergency key within the fob. Did you even read your manual?
The emergency key will only open the driver door. There is no key slot on the rear hatch to offer an emergency open option.
There usually is a way to manually actuate the latch, but you would have to put the rear seats down and crawl back there. Most vehicles have a little plastic panel that can be removed to gain access. This is more designed so it can be opened in case of a mechanical/electrical failure.