Under this section https://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters look for the nested meta query example, it’s the last code example in the section. Basically you need to do the query you’re doing in a nested query with the relation of ‘OR’ and the add another query at the top level that does and ‘AND’ to make sure the end date is < today.
Hope that helps.
