I wouldn't focus so much on how you can get your hourly rate TO $125, but rather think of it as 'what can you offer to make your hourly rate worthy of $125.
Is anybody really looking for a PHP/MySQL programmer? No. They are looking to get a product/service/feature etc. built. What do you offer in that equation. I suspect that your experience with the language is only a portion of that.
It isn't always easy to figure out what soft skills you bring. Why do you program? What do you really like about it? Do you like creating beautiful code? If so, only so many clients will pay extra for that. Are you able to make systems run with incredible efficiency, so the client could save on server costs? That may be worth the extra $$ to them. Are you good at designing usability? If that is a missing piece, that may be valuable as well.
I've found 'what can I offer' is better than 'what can I get'.