explain plan for
select * from person
where person_id = 3
;

plan FOR succeeded.

select * from table( dbms_xplan.display );

Plan hash value: 3101872853

--------------------------------------------------------------------------------------------
| Id  | Operation                   | Name         | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |              |     1 |     8 |     1   (0)| 00:00:01 |
|   1 |  TABLE ACCESS BY INDEX ROWID| PERSON       |     1 |     8 |     1   (0)| 00:00:01 |
|*  2 |   INDEX UNIQUE SCAN         | SYS_C0010997 |     1 |       |     0   (0)| 00:00:01 |
--------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - access("PERSON_ID"=3)