The answer to this question in MBB at least is less about will you be here in 5 years and more about how does MBB fit into your 5 year plan. Think of it as an alternative question to why this firm? I recommend the following
1. Be genuine - if you say you see yourself in consulting in 5 years but your other answers or past data do not support that then it reflects poorly
2. Tell a story - Tell them where you have come, where you are headed and how this role helps you get there.
3. Focus on the skills - as Ian said, make it more about what you would like to be doing (e.g., helping leaders in x industry navigate challenges they face) and less about the role (e.g., CEO of a small pharma company)
4. Be well researched - know exactly the skillsets you will develop in this role that will help you progress in your career
5. Be open minded - No one actually knows what will happen in 5 years so be open to different possibilities
6. Be respectful - you may not want to be in consulting but do not talk negatively about consulting (e.g., unsustainable lifestyle or too much travel) in the answer
All the best!