Someone recently removed a post in this forum, asking about the minimum round time; I'm guessing the OP found the answer and removed their question - but that means that anyone else wondering the same thing doesn't get to see the answer, so here we go:

MTR Appendix B is what we're looking for, re: round times:

The required minimum time limit for any match is 40 minutes.
The following time limits are recommended for each round of a tournament:
• Constructed and Limited tournaments—50 minutes
• Single-elimination quarterfinal or semifinal matches—90 minutes
• Single-elimination final matches—no time limit

The emphasis is part of the MTR, not my addition; the point of emphasis is that 40 minutes is required, but 50 is recommended (for most rounds).

d:^D