I don't think you will find one because the PC Card format is not fast enough.
I found an adapter "ExpressAdapt PCMCIA PC CardBus to USB Mode ExpressCard Adapter" on this site :
http/www.synchrotech.com/products-expc/pcmcia-pc_cardbus-usb-expresscard-adapter-expressadapt.html
But it is working with USB 2.0 Mode ExpressCards only.
Okay, but as I wrote in my original question: I just bought an "express" card USB3.0 adapter. I'm seeking an USB3 adapter with the older PCMCIA interface - not an "express" interface. I guess no one makes one. I know about the transfer speed but it would have to be faster than USB2, I'd think.