Yes cycling and going for a bicycle ride or riding an exercise bike is good for knee joint pain and helps lubricate your joints.
I get occasional knee joint pain myself and after going cycling and on bicycle rides my knee joint pain has diminished and I feel much better and full of energy now that I go for a bicycle ride at least every few days.
I try to ride my bicycle everyday but sometimes it's too cold so I then use my indoor exercise bike for getting my knee joints moving.
Cycling is also good for your heart health and can prevent diabetes as well as lower your blood pressure and you might live longer and not end up in a wheelchair in your old age.
Staying active as in walking, cycling, jogging etc helps people stay healthier, improves heart health, lubricates your knee joints, gets the blood flowing and can help prevent dementia, diabetes, heart disease and stroke.