If somebody were bold enough to wish to annoy the king with such an announcement they would say something like "Su Majestad, Juan Carlos I, Rey de Espana, esta en la tienda"( His Majesty, Juan Carlos I, is in the store).
However, the impression I get is that Juan Carlos would much prefer to take care of business and leave with as little fanfare as possible. He probably would not go to a store anyway.
Carlos es simpatico.
Con Carlos, por favor.
The literal translation is... carlos tiene suerte
The eqivalent of "John" in Spanish is "Juan". To make this the diminutive "Johnny", You would say "Juanito".
"Canto a la casa de Carlos".
The Spanish word for store is "Tienda".
Juan Jiménez es su primo
¿Juan toca el piano?
primo Juan
"John" in Spanish is "Juan". It is pronounced "Hwahn". Please see the Related link below for confirmation of the translation.
Julian y Carlos son de la Habana
Carlos, translated like this when possible.