OK. As long as the yeast is viable, I would think that you would see action soon. The one time I fermented in the mid 60's *F it took a while. I do hydrate the yeast for a little longer than that, a couple hours in cooled boiled water and extract. I do this to ensure that I am pitching viable yeast.
The other thing you could check is whether you have a good seal on your fermenter bung/lid. If there is a leak, it could be starting without building pressure, though you would start to see a krausen. Are you using a bucket or a carboy? if a bucket, lightly press the lid and see if the airlock moves, indicating that it is building pressure. bungs normally seal well. If you feel a little pressure, then it is going, and is just a slower starter. I would give it to mid weekend and then possibly repitch some more viable yeast.