The stretched Wolves' lead at the top of the table to six points with just three games remaining after nearest rivals Birmingham and third-placed Sheffield United, a further point behind the Blues, were held to home draws by Plymouth Argyle and Nottingham Forest respectively.
Another win on Saturday would guarantee Wolves' return to the top flight, but McCarthy was quick to play down that notion.
"That's dangerous. They will all be wanting the carnival stuff and the fanfare and turning up and giving it large and the big yahoo, but it's business as usual as far as I am concerned," said the Yorkshireman.
A moment of brilliance from Keogh gave Wolves the lead after seven minutes at Derby before Przemyslaw Kazmierczak's free-kick brought the hosts level on the half-hour mark.
Mile Sterjovski put the Rams ahead 10 minutes after the break and Matt Jarvis restored parity midway through the second half.
It looked like Wolves would have to settle for a hard-earned point but Keogh sent the travelling Wanderers faithful into ecstasy with a headed winner three minutes from time.
McCarthy was scathing in his assessment of his side's performance but singled out matchwinner Keogh for some special praise.
"We were hopeless. We were awful. We were rubbish. We couldn't play any worse and we won the game. We were bobbins, except for Keogh and Jarvo (Matt Jarvis) and the front lads," said McCarthy.
"But we kept going and winning games is not always about playing free-flowing football. There are lots of ways to win games and sometimes you have to do it ugly, and that's what we have done.
"I am thrilled for Andy Keogh. He wasn't flavour of the month with me in the first half when he kept turning and not laying the ball off. He is now though.
"He's fantastic. He put a real shift in and he deserved his goal. He hasn't scored for a while and I asked him what that 'Keogh, Keogh' chant was because we haven't heard it for a while."
Derby are still not safe from relegation. The Rams are five points above the drop zone but have a game in hand over most of the teams below them.
After only one win in their last seven matches, Nigel Clough admits his side are toiling in their attempts to make themselves safe.
"It is taking a while. We are just limping to the end of the season trying to get that win or draw or anything that might make us safe," said Clough.
The former Burton boss then admitted that he imbalance in his side is driving him up the wall.
"I think some of the things that we did in the second half were either very good or very bad, and the bad things cost us the goals," he said.
"We didn't do enough with our chances and we certainly didn't do enough in our penalty area, hence the 3-2 scoreline.
"If we can get a back four out that can defend and play like that going forward then we can be encouraged from that point of view.
"If we had got a third or a fourth goal then we might have got a point.
"The inconsistency (at the back) is driving me mad. We go to Sheffield United and play well and concede four goals, we play well at Cardiff and concede four again and play well today and concede three."