Do we have working weaponized laser technology in 2010?
if "working" means "deployed, then AFAIK, no. As others have pointed out, there's been a lot of money spent and a lot of work done, but I don't know of anything deployed. There are rumors, of course.
If working means "has anyone destroyed something that might look like a military target with a laser" then, yes, lasers have been occasionally shooting down target drones for 3 decades.
Now, as to how the modern laser fits the "death ray" description - AFAIK, nobody's ever been killed by a laser, so "death ray" isn't too applicable 67 years after Cayce's prediction.
However, as I read Cayce's text, the whole "Death" part seems to be a red herring. Frankly, I'm having a lot of trouble following Cayce's description, but it doesn't seem to discuss much killing with the "death ray." Instead, it was used to "alter or change the ENVIRONS" needed by the "enormous animals that once roamed the Earth." As others have noted, the "Death Ray" or "super cosmic ray" was sent out from "various central plants." The upcoming discovery of the "death ray" was associated with the stratosphere or cosmic rays.
So, the predicton was a "Death Ray" that could be used to change the natural environment to drive "enormous animals" extinct, emanated from various central sources, associated with cosmic rays and the stratosphere, found by 1958.
Frankly, the *only* connection between this and the laser was the patent date of the laser and, arguably, the word "ray."