Laravel order by starts_at and ends_at within current date

How can I pin to top one or more results that have starts_at and ends_at dates between the current date?

For exampe:

**Suppose Current Date: 2018-10-05**

|      name |            starts_at |              ends_at |           created_at |
|-----------|----------------------|----------------------|----------------------|
| Example A |               (null) |               (null) |  2018-10-05 00:00:00 |
| Example B |               (null) |               (null) |  2018-10-04 00:00:00 |
| Example C |           2018-10-01 |           2018-10-03 |  2018-10-03 00:00:00 |
| Example D |           2018-10-03 |           2018-10-05 |  2018-10-02 00:00:00 |
| Example E |           2018-10-05 |           2018-10-07 |  2018-10-01 00:00:00 |
| Example F |           2018-10-07 |           2018-10-09 |  2018-09-30 00:00:00 |

Since Example E have starts_at and ends_at between the current date, Example F has starts_at in future date, Example C and Example D has ends_at in past date, Example A and Example B does not have any, the order should be:

Example E
Example A
Example B
Example C
Example D
Example F

My current eloquent order by query is:

Example::orderByRaw('if(isnull(starts_at) >= curdate() and isnull(ends_at) <= curdate(), starts_at, created_at) desc');

And it just return:

Example A
Example B
Example C
Example D
Example E
Example F

I also created a sqlfiddle.