I don't know of a way to access the contents of a cell array as part of a query. I had a similar issue in which I wanted to access the contents of a numerical array, but the only way I could think to do it was to construct the string:
numericArray = [1 2 3];
preliminaryString = sprintf('%d,',numericArray);
stringList = ['(',preliminaryString(1:end-1),')'];
This gives the string '(1,2,3)' as result, which I then use in my query.
I'm afraid you'll have to do the equivalent for your cell.