That's a good question. "Killer Queen" was from their 1974 album "Sheer Heart Attack" and charted the same year. I'm not sure when Queen toured with ELO - do you remember?
I believe I saw them in ‘78. I don’t recall hearing Killer Queen, but then, I wasn’t familiar w the band going into the concert and I doubt I would recall, at this point, individual numbers. I actually went to hear ELO because, frankly, I was invited and a guy bought the ticket. ;)