binary forces the comparison to be performed byte-by-byte rather than character-by-character. This means that they have no character set, and sorting and comparison are based on the numeric values of the bytes in the values.
More on binary:
Your query is looking for exact comparisons on the password and email address but is using a LIKE comparison on the uid. Why? Although you are limiting the result set to a single row (LIMIT 1) you still have the possibility of multiple rows from which you will select but 1.