If you did not know already, you are now learning that, in China, many (if not most) native (Chinese) teachers of English know barely more than you do, so they often know only one way to express an idea.
Also, Chinese schools do not encourage inquiry, debate, or independent thinking. A test will have a certain number of questions, and an equal number of acceptable correct answers. But of course English is not that simple! There are often several ways to express the same meaning.
That said, in your second example, before is the preferred response, in my opinion. I think of doing something active and totally filling all the time "until" some later time, such as, 'We played cards until it was time to board the plane' meaning we didn't do anything else during that time. 'We played cards before boarding the plane' means that we played cards, but perhaps we did other things as well OR that playing cards was the last thing we did immediately before boarding. Perhaps a better example of that would be 'I went to the restroom before boarding the plane.'
Context is very important in choosing between waiting before and waiting until.
Circling back to your original example, I would most likely say it a different way: 'We waited over an hour to get our food.'
Student or Learner