How to decrypt MultiBit private key with 128 bytes line and 52 bytes line?

I want to recover my bitcoin private key stored by MultiBit. I’ve written down private key as text while using MultiBit classic. I don’t remember how I get the text of private key. The text consists of two line. First line has 128 characters and starts with U and contains +. Second line has 52 characters and starts with q, contains /.

As far as I know, the text may be encrypted. And I also wrote down password, so I assume I can decrypt the text with the password, but I don’t know how.

I’ve tried the instruction of Export and limited import of private keys with pasting the text to a file and executed the openssl command. However, I’ve got bad decrypt message and 64 bytes result file. It doesn’t seem successful.

I want to how to decrypt my private key text and get valid private key.