This restaurant is located on the western promenade (Paseo Marítimo Antonio Banderas nº 6) and hence on the way to the airport if you take that route (which is something I do very often since I live nearby).
I have taken many people there on business lunches on our way to the airport.
Is your flight departing at 17.00 or you have to be a the airport at 17.00? I don't think the restaurant is open before 13.00, but you certainly have time for a lunch around that time (please note that if you pop in before 14.00 odds are you'll be alone at the place. It will be bustling by 15.00 though).
You can get to the place by the #16 bus getting off at the 1522 (Parque Mediterráneo) stop and walking south to the beach for about half a kilometer.
From the restaurant to the airport you can go back to María Zambrano train station using the same bus and from there take the train to the airport, or if you are tight on schedule just hail a taxi at the street which is by the promenade (C/ Pacífico) - it is a short ride.