Only time paying off a CC in full can really ding your score is when you PIF one card then open another. Generally this happens when moving a balance from a high interest card to a low interest card. It can adversely affect your score a bit as you appear to be "rate shopping".
To avoid this, leave about $100 on the old card, and pay it off over a 3 month period at about $35 a month.
Since you're keeping the card, it should not matter. But, if you want an once of prevention, pay off everything but a $100, then pay that off over 3 months till you hit a zero balance.