usually it is quite quick (around 5 mins) I think your plates are just too wet. You can open the plates and invert them in a laminar flow hood prior to spreading to dry the plates. Or you can invert the plates next to a flame to do the same.
Maria Attallah Its quite unusual, 45 mins time is too much. If you are spreading culture on already prepared/ dry plate then 2 mins are enough to get it dry inside the laminar flow hood. You should let this plate dry before spreading your culture, otherwise wet plate could get contamination.