I had the same problem. You can but a replacement key and nuts the same as the lost one for $54.99 at the ford dealership.
Give them your VIN so you get the correct one but the wheel pictured is the 17" titanium wheel same as mine.
Part#: 1A043 Kit Wheel Locking
https://parts.ford.com/shop/en/us/nut-wheel-6465465-1#sectionId:4343896