Answer
No, Lucas Vázquez was not a part of Spain's Euro 2020 squad. He was left out of the squad by manager Luis Enrique, who instead chose to go with younger players such as Ferran Torres and Dani Olmo. Vázquez had been a part of Spain's squad for the previous two major tournaments, the 2018 World Cup and the 2016 European Championship, but he was not selected this time around.