The Napoli winger has been in prolific form this season and is hoping to add more goals to his tally before the end of the term in a bid to boost his Brazil 2014 chances
The former Real Madrid man has 14 strikes in all competitions already in this campaign and is well on course to achieve his goal, but has yet to feature in a full international for Spain.
"I want to score more than 20 goals," he told Sky Sport Italia.
“The World Cup? Yes, it’s a dream of mine to play there with Spain."
Callejon netted in Napoli's convincing 3-0 Coppa Italia victory over Roma in midweek to seal a date with Fiorentina in the final, and the 27-year-old says it was a statement of intent shown by the Partenopei.
He added: "The Roma game was a show of force; we have shown ourselves to have a great mentality."
The winger also had praise for attacking team-mate Gonzalo Higuain, who joined Rafael Benitez's side from Madrid and has 12 goals to his name in Serie A this season, and looked ahead to his side's encounter with Sassuolo.
"As far as I’m concerned, Gonzalo is the most decisive player in Italy," he continued.
"We have to give 100 per cent in every game, so we must continue to work on Sunday. It is an important game, we need the three points."
Third-placed Napoli are four points behind Roma in second in Italy's top flight.