Go to the CEO and say, "I have a big scalability improvement that I could easily make which I've been told not to do because we're afraid that you'll misinterpret how efficiently our database is being used."
He'll get upset, but it won't be at you. And the political barrier to the solution will melt away. However the person who he gets upset at is likely to become unhappy with you. OTOH the CEO is likely to be relatively pleased with you, but that might not help you very much.
I suspect that very few people would choose that solution...
Cheers,
Ben