There are a good number of pico-second resolved X-ray crystallography papers published. Schotte, the author here, published her first in 2003 on Myoglobin. Many others have used this since the early 2000s. Other protein watching techniques such as NMR have been exploited for small time resolution, as well.
The frontier to be talked about is single molecule resolution. Equilibrium measurements, like X-ray crystallography, are still incapable of picking up states of the protein with very low populations, which are often relevant to conformational change.
It can be a bit of misnomer, as well. Time resolution of often means using a singular value decomposition to pull out populated states from the data. As a result, the pictures isn't exactly time linear.