SELECT TIMESTAMPDIFF(
	MINUTE,
	STR_TO_DATE('Tue Oct 23, 2018 - 19:57:12','%a %b %d, %Y - %T'),
	NOW()
);


##</code><code>##

SELECT
    column_name,
    TIMESTAMPDIFF(
        SECOND,
        STR_TO_DATE(column_name,'%a %b %d, %Y - %T'),
        NOW()
    )
FROM table;