20 seconds is a long time. Perhaps the release needs adjusting.

For SPD pedals...Try turning each screw counterclockwise 1/4 of a turn (same amount on both pedals) and see if they release a little smoother. Keep adjusting 1/4 a turn until you can unclip smoothly. BUT don't take the screw out completely, because it'll be next to impossible to put the thing back together.

I had to unscrew mine 1.5 turns.