What should I do after mistakenly using moldy paint on drywall?
Mold need two things to create spores, water and air.  You probably killed any active mold when you mixed it in the bucket.  However, don't fear. Once that coat is dry, recoat with fresh paint. It will seal over the original coat and any surviving  mold should be encased and die. I think you will be fine, just repaint.