This so far has varied for me. Usually I do not see them lock up for a few hours, but some have waited a day or 2. This is why it is generally a rule of thumb of 3 days in and 3 days off. If the male locks the first day, as soon as they are clearly done, he is taken out and still gets 3 days off. After his 3 days off, I will put him back with the female or another female if I am attempting to breed him to multiple females. Rinse and repeat until ovulation. It is a game of true patience.
I myself have a pastel female that is clearly wanting to breed. She does the tail wagging as soon as I put a male with her. I have put several males with her in the last 2 months, yet none have locked with her, that I have seen. Even males that are breeding with females.