I think it may be the best anyway, even if you could find some kind of gasketed, hardened, wet location, listed, floor mount receptacle. It will be a lot better protected under a trap door when in use and be normal parts you can find a few years later.
when you raise the rec it is about 6 inches high the outlet is vertical with an in use pop out cover. When not in use you slide the receptacle down flush with the deck
Getting it UL Listed for use outdoors in the rain and snow will be a challenge.
I like Greg's idea. I did something similar for the Christmas tree on my deck by making 1 of the deck boards removable between the joists. It's only 1 joist space long, but when it's in place it looks perfectly normal; but I can lift it out in a few seconds. If you cut a tiny notch in the edge of it you could plug in your cord and replace the board whenever you need power.