"If you don't leave your current job, what do you imagine you will be doing in several years?"

There are several things the interviewer wants to learn from this question. The interviewer knows you are looking for another job because you are not happy with where you are at. Knowing this, they want to find out how you react to situations where you are not happy. Most people who do not prepare for this question will have a generic answer that doesn't stand out. You can use this opportunity to give a solid answer.

"I'm confident I'll be in a management position several years from now. In my current position, junior employees ask me many questions and I like to mentor people. My work is very routine and I'm very efficient. I want to find more challenges my work currently doesn't offer."

"To tell you the truth, I feel I'll be doing the same thing I'm doing now. I always look for more work and different opportunities, but my current company doesn't have many opportunities for advancement."

"I'm a very proactive person and I'll continue to do my job well. I'll always look for opportunities and even create places where I can improve my work. I know if I continue to perform well, I'll have more opportunities to get promoted when a position opens. So hopefully, in several years, I'll be managing people that are in my current position now."

Despite having some negative feelings about work, this answer shows that he or she will continue to do hard work regardless of being unhappy. You shouldn't say you are unhappy, but looking for another job is one indication of not being happy.