LEO is 0.0005% of the way to the Moon, and yet once we'd done the first it didn't take us long to scale up to the second.
Let's say it takes ~8 minutes to get to LEO vs 4,380 minutes to get to the Moon. That's a factor of ~550x longer flight time for a distance 2000x further.
Alpha Centauri is 1500x further away than Mars. It currently takes ~7 months to go from Earth to Mars (at 25,000 mph), assuming similar scaling that comes out to only 400x the flight time, or just about 230 years.