I'm in my late 30s but never in my entire life did I get delayed-onset muscle soreness (DOMS) from cycling. But even walking at a slow-moderate pace (less than 6 kmh / 3.7 mph average) for 2-3 hours gives some DOMS.
I climbed 20% percent hills going all out, I went on long rides at moderate pace, I went on short, full throttle rides, I tried climbing the local hills in the hardest possible gear, I tried climbing standing for 10 minutes straight, I am capable of maintaining 95% max heart rate for 20 minutes and 85% max heart rate for one hour. Max heart rate of 182 was measured by monitoring it for a few years and I'm able to reach it when sprinting at the end of a hard climb. Never, not once, did any of that result in even the slightest amount of DOMS. If it matters, I currently weight 70kg at 1,74m (154 lbs, 5'8) which is stable for a few years.
When someone mentions DOMS in the context of cycling, to me it's like saying 1+1 doesn't equal 2. Please enlighten me.