dwdrums, You make the call.
A couple of years back I had my 81 H22 swing keel at a mooring with mud/rock/old 6" pipe 'bottom' in the arc of the boat's swing. At low tide it was not a problem as I had ~2' clearance, BUT an astronomical low tide combined with some wave action...the pipe (assumed) severely damaged my keel.
It was a PO-repaired swing keel and was not done with the best of quality, so I was not too surprised. Nonetheless, it was a calculated risk with some immovable objects... I lost. Replacement cost: $1100. Assuming you have an '80s H22 with a 1 1/2' draft - keel up, it's only a foam reinforced fiberglass keel. You say you have 'soft' mud...consider any wave/wind action that could exacerbate repeated impact forces.
I have since moved to where I have ~8' clearance at low tide so I could even keep the keel lowered, if desired (mud & grass bottom, immaterial now).
You make the call.