Recently, I stumbled upon this video by Simon Sinek about mentorship. It explains something I wasn't aware consciously, so I think this is really worth sharing - that mentors shouldn't be asked out of the blue, but rather this is something that becomes and evolves with time, like friendship. You don't ask someone to "be your friend". Rather, you meet more or less regularly, make time for each others, get to know each others, etc.
When I was starting work, I asked an executive for mentoring me directly. Of course he declined, and kindly asked my manager for a good fit. That was a bit bold of me, but also too direct. Truth is, I was really interested in his point of view. I then had to wait a few years before being more in contact with executives, which I find very useful because they usually have a deep understanding of the business and the big picture. They are aware of the why and of the compromises necessary.
In any case - get yourself mentors. Not one, multiple, to get a clearer view on your issues and opportunities.