MySQL - How to store AES_Encrypted data?
Many encryption and compression functions return strings for which the result might contain arbitrary byte values. If you want to store these results, use a column with a VARBINARY or BLOB binary string data type. This will avoid potential problems with trailing space removal or character set conversion that would change data values, such as may occur if you use a nonbinary string data type (CHAR, VARCHAR, TEXT).
Source: http://dev.mysql.com/doc/refman/5.5/en/encryption-functions.html
If you need to use VARCHAR, rather than BLOB, then convert the encrypted binary to Base64 which only uses printable characters and can be safely stored as VARCHAR. Of course you will need to convert it back from Base64 to binary before decrypting.