Just throwing it out there, because these are priced even better than the ones I bought last year on eBay:
www.uhs-hardware.com
Specifically for the 453 and in the right frequency.
I got mine cut and had the car programmed by a shop in Salinas, CA.
After a nerve wracking multi-hour wait, but everything is working fine.
I have no association with the vendor, I just received a random email and thought others could benefit.
Jim

2015-2017 Smart Fortwo Forfour (W453) / 4-Button Flip Key / VA2 / CWTWB1G767 / 434 MHz (AFTERMARKET)
RFK-MB-4244 Brand New Aftermarket Replacement For: FCC ID: CWTWB1G767 IC: 178890-FWB1G767 Chip ID: Chip: 4A / PCF7961M Frequency: 434 MHZ Battery: CR2032 Button: Lock, Unlock, Hatch, Panic Aftermarket Flip Blade Included Test Key: VA2 Manufacturer: Keyless Factory Compatible with the following...

Specifically for the 453 and in the right frequency.
I got mine cut and had the car programmed by a shop in Salinas, CA.
After a nerve wracking multi-hour wait, but everything is working fine.
I have no association with the vendor, I just received a random email and thought others could benefit.
Jim