If using @DBLookup, you would have to make the view column a concatenation of the fields you’re looking for, e.g.:
Column formula = field1+~+field2+~+field3
Note that the tildes make it clear where one field ends and another begins.
Then, use the same formula for your key in the @DBLookup.
Or, if you want to use script, you can use the GetAllDocumentsByKey method of the NotesView. This lets you use an array of key values as long as the order is the same as the order of the sorted columns in the view. Check the designer help for more details.