The original Legend of Zelda, unique in the series, not only has keys that can be used in any dungeon, but you can even buy keys, for considerable expense, in shops, for either 80 or 100 rupees.
But, is the purchase of keys ever necessary? Usually Zelda 1 gives you many more keys than you need. Even in the Second Quest, which tightens the screws, you can usually get by if you just make sure to clear every room and bomb some walls.
But consider the worst-case scenario. What if you open just the wrong doors? Is it possible, if you waste keys on rooms that aren’t on the critical path to completing the game, to make it so you have to resort to buying keys in shops?
In an 11-minute video, “TheRetroDude,” as he styles himself, examines this question. tl;dw: not in the First Quest, but it’s technically possible to soft-lock yourself, unless you resort to commercially-provided keys, in the Second Quest, if you’re very injudicious about the doors you open. Here:
Trying to Get Stuck in Zelda 1 (Youtube, 11 minutes)
