The former Barcelona midfielder was lined up to provide cover for the injured Lucas after leaving Chinese club Dalian Aerbin.
But Keita decided that mid-table Spanish side Valencia were a more attractive option.
"When we received the call from Valencia, talks with Liverpool were at a very advanced stage," Keita said.
"But then I told my agent we were going to Valencia. I did not doubt for a second.
"When I came to play at Mestalla with Sevilla or Barcelona I suffered a lot to win, because this is a really big club, with fantastic fans. That is why I opted to come here."