Downshift to a lower gear and start looking for the best path to steer to. You can apply the parking brake but don't expect it to help much, many parking brakes are not designed to stop a moving vehicle.
Yes . Over time brake fluid can leak out and cause a failure.
pray
Contaminated brake fluid.Rusted, rotted brake lines.
Parking brake is on, Brake fluid is low, Hydraulic failure of the brake system.
The Key hole is an emergeny shift system in case there is a brake pedal failure in the car you stick the key in that hole to shift out of park without applying the brake first
get your btrakes checked regularlly
Your brakes are failing
Brake Failure
Get it repaired
These cars had issues with the pedal pressure sensor located in the brake booster. Additionally the brake booster it self is also known for failure on this car.
Have them repaired immediately by a professional.