Best way to search in top n rows in sqlite

I have a BIG transactions table. I want to to find a specific field(card number) in transactions inserted in last one minute, Therefore it is not reasonable to search the entire table. So i want to search just in top 20 rows.

Here is the my code:

public boolean isCardTapedInLastMinute(String date, String time,String UID) {
    String oneMinuteBefore = getOneMinuteBefore(time);
    String tables = TRX.TABLE_NAME;
    String[] columns = {TRX._ID};
    String selection = TRX.COLUMN_NAME_TRX_DATE + " = ? AND " +
                       TRX.COLUMN_NAME_TRX_TIME + " >= ? AND " +
                       TRX.COLUMN_NAME_CARD_ID + " = ?";
    String[] selectionArgs = {date, oneMinuteBefore, UID};

    String sortOrder = TRX.COLUMN_NAME_TRX_DATE
            + BusDBContract.SORT_ORDER_DESC
            + ", "
            + TRX.COLUMN_NAME_TRX_TIME
            +  BusDBContract.SORT_ORDER_DESC;
    String limit = "1";
    Cursor cursor = query(selection, selectionArgs, columns, tables, sortOrder, limit);
    if (null == cursor) {
        return false;
    }
    if (!cursor.moveToFirst()) {
        cursor.close();
        return false;
    }

    return true;

}

and the query method:

private Cursor queryWith(String selection, String[] selectionArgs, String[] columns, String tables, String sortOrder, String limit) {
    SQLiteQueryBuilder builder = new SQLiteQueryBuilder();
    builder.setTables(tables);
    Cursor cursor;

    try {
        cursor = builder
                .query(
                        mBusOH.getReadableDatabase(),
                        columns,
                        selection,
                        selectionArgs,
                        null,
                        null,
                        sortOrder,
                        limit);
    } catch (SQLException e) {
        Log.e(TAG, "[query]sql_exception: " + e.getMessage());
        return null;
    }

    return cursor;
}

It is working correctly and it searches the entire table. It takes about 50-100 ms to be performed for 15000 rows but it may be bigger and i want to optimize it by searching in top 20 rows.

What is the best way to do so?