Use:
SELECT *
FROM YOUR_TABLE t
WHERE t.datetime_column < DATE_SUB(NOW(), INTERVAL 24 HOUR)
AND t.datetime_column > DATE_SUB(NOW(), INTERVAL 48 HOUR)
Use:
SELECT *
FROM YOUR_TABLE t
WHERE t.datetime_column < DATE_SUB(NOW(), INTERVAL 24 HOUR)
AND t.datetime_column > DATE_SUB(NOW(), INTERVAL 48 HOUR)