Is it the rubber part you don't like? You could probably hack the rubber off to make it thinner, but you'd destroy the chip that's in it and wouldn't be able to start the truck, just unlock it.
Even easier, if you need a spare key just to get in and not start the car. The Toyota dealerships have metal keys that you can get cut the same. They will unlock the car and glove box but thats it. You don't want to try and use it in the ignition.
if its a spare "valet" key, it will only open the doors, not glove box. I dont have one, and not sure if toyota makes them, but I know a lot of spares are actually valet keys
Dealership can cut and program valet keys for you, you just need to specify you want a valet key. Simple way to tell is that gray keys are valet and black is master.
Or you can get one of those super-strong magnet cases that hold a spare key in it. I got one hidden way up somwhere that youd HAVE to know where it was and just which contorted-arm-double-jointed-elbow position youd have to be able to do just to get a finger on it.