Yes and no. It really depends on what you want to learn.
Yes, I could show someone how to play something within an hour, and they would happily go on there way with a big smile on their face. But if they wanted to progress past one simple song, then the answer is no. Even if you want to learn a few straight forward songs, then you still have to practice and put the hours in.
It also depends on your own natural musical ability. Some people are able to pick things up quickly, so it may easier for them. However, most people still have to practice for years if they want to be really good. Learning to play the piano can be compared to a lot of things, like learning to drive, or learning to play tennis, or learning a new job. It always takes time and effort.
The basic rule is – ‘The more you put in, the more you get out…’