Anywhere between 5 mins and 48 hours.
I have been implementing musing for quite a while now and I think their voting system is based on user ranking. I think. I am not certain. As for me, my vote comes in after 72hours. Tops. And I have seen some people whose votes come in 2houra to three hours later. On another look at it, I think it depends on the curator in charge of voting for the different categories of questions being asked on here. The different curators having different niche, take different time frame to analyse and vote on the answers provided by us.