SQLite supports the standard SQL variables CURRENT_DATE, CURRENT_TIME, and CURRENT_TIMESTAMP:
INSERT INTO Date (LastModifiedTime) VALUES(CURRENT_TIMESTAMP)
The default data type for dates/times in SQLite is TEXT.
ContentValues do not allow to use generic SQL expressions, only fixed values, so you have to read the current time in Java:
cv.put("LastModifiedTime",
new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));