Barry Allen mentions a shelter on the corner of Fox and Gardner. Gardner Fox is the creator of the Golden Age Flash.
Jay Garrick and his wife have their 70th anniversary so this makes them nearly 90 years old at the youngest.
The events depicted take place on February28th, and on February 28th 40 years ahead in the time line.
Bart Allen is the future grandson of Barry Allen, AKA the flash. He travels back in time to save his grandfather.