Tower Local Controller reported they forgot they allowed Ground Control to taxi an aircraft across their runway and cleared another aircraft for takeoff.

Narrative

This was my first day back to the facility after a 3 day weekend. I initially worked Ground Control then slid over to work local 1 after about 50 minutes on position on Ground Control. It was routine traffic for the time of day. A high number of departures and arrivals and traffic pattern. Traffic was slowing down and at this point I had been on position in the Tower cab approaching an hour and 20 minutes. I issued Ground Control a conditional crossing to an Aircraft Y to cross Runway XXL at [Taxiway] XX behind a departing IFR Aircraft Z and that there would be traffic holding in position on Runway XXL full length. XX taxiway is 3;769 ft. from the approach end of [Runway] XXL where the traffic holding in position was; which was Aircraft X. After my Aircraft Z was airborne and I had adequate separation; I told Aircraft X to fly straight out and cleared them for takeoff on Runway XXL. I was looking out my window at Aircraft X and at the approach end of the runway; and also looking at my final because there was another Aircraft A on a mile final or so awaiting clearance. I completely forgot about the runway crossing at [Taxiway] XX. The Controller in Charge (CIC) asked me what I was doing since I allowed the crossing then realized that Aircraft Y was crossing the runway at [Taxiway] XX. I immediately attempted to cancel Aircraft X's takeoff clearance but instead I accidentally told Aircraft A to cancel takeoff clearance; but they were on the upwind of [Runway] XXL. Aircraft A read back 'cancel takeoff clearance' but the aircraft at the approach end continued to roll slowly; I thought they were just powering down planning to exit the next taxiway. However; Aircraft X continued to roll; and I was confused. By the time myself and the CIC figured out I said the wrong call sign Aircraft Y was well across and off of the runway and Aircraft X had just begin to lift. I then resumed normal operations and continued working traffic and stayed on position for almost 2 hours and 25 minutes. Conditional crossings are very standard at ZZZ; this is something I have done hundreds of times since being certified. We have visual aids to remind us of crossings which are flashers that flash and make noises to remind controllers the runway is occupied. I was just in muscle memory mode working traffic; doing my best and completely forgot about Aircraft Y crossing downfield. There are already procedures in place to alleviate this situation from developing. My only recommendation in the future is just do my job better and be more vigilant. This is something that is a daily occurrence that happens multiple times a session.