The following update works perfectly in SQL, I just need to add it to Cron/Convert to php:
UPDATE mdl_quiz SET timeopen = UNIX_TIMESTAMP((CAST(CAST(CURRENT_DATE() AS DATE) AS DATETIME) + CAST('10:30' AS TIME))), timeclose = UNIX_TIMESTAMP((CAST(CAST((CURRENT_DATE()+'1') AS DATE) AS DATETIME) + CAST('22:00' AS TIME))) WHERE id in ('62','78');
UPDATE mdl_quiz SET timeopen = UNIX_TIMESTAMP((CAST(CAST(CURRENT_DATE() AS DATE) AS DATETIME) + CAST('10:30' AS TIME))), timeclose = UNIX_TIMESTAMP((CAST(CAST((CURRENT_DATE()+'1') AS DATE) AS DATETIME) + CAST('22:00' AS TIME))) WHERE id in ('62','78');