I think not.
But for the sake of discussion, let's say you wanted a minimum time of 1 hour. And let's say the person finishes the task in 10 minutes. Do you really want the person to just leave his/her browser open for another 50 minutes so that it can look like they spent an hour on the task?
In a moodle quiz, you can set allowed time. In my above example, let's say that you said "You have one hour to take this quiz." If you setup the quiz to automatically submit when time runs out, then you could tell students "Don't manually submit, I want it to look like it took you the full hour by letting moodle submit for you." and you might then be satisfied, right?