How about a pair of long tweezers to try and shift it? Use a rubber spatula to open the snake's mouth. Great care must be taken not to perforate the esophagus, but if you can pull one side of the rodent back out, perhaps you can reposition it.
(After an entire hour, I would be concerned as well).

For folks who think it's not an appropriate sized mouse, don't count on it. Snakes are capable of swallowing things that are twice their girth--it's just not recommended!