Bought sex toy used 4 hrs later at store they took it out to show it worked what if someone ejaculated on it bef i bought? could that get me pregnant?

Unlikely an issue: Four hours of drying would immobilize/kill and tiny sperm you would not be able to see. Be cautious of any such purchase & think ahead to cleanse such items to your satisfaction before use.

Sex toy: Sperm don't live indefinitely in air. I would hope that no one would be ejaculating on sex toys that are on the shelf at the store. However, infections can sometimes be passed through dirty sex toys.