You can do something but there is inheritance and where could be complicated. if you are sure that the template is assigned directly to this particular cms.menuitem page and note inhereted from the parent, you can do something like
(isnull(NodeInheritPageTemplate,0) = 0 AND NodeTemplateID <> (select PageTemplateId from cms_pagetemplate where pagetemplatecodename = 'FormTemplate'))
AND
(isnull(NodeInheritPageTemplate,0) = 0 AND NodeTemplateID <> (select PageTemplateId from cms_pagetemplate where pagetemplatecodename = 'FormTemplate'))
but I would recommend the solution with boolean field