We check if pick list is created against them but there's no index so we
end up reading entire table.

```
+------+-------------+------------------+-------+---------------+----------+---------+------+--------+-----------+----------+------------+-------------+
| id   | select_type | table            | type  | possible_keys | key      | key_len | ref  | rows   | r_rows    | filtered | r_filtered | Extra       |
+------+-------------+------------------+-------+---------------+----------+---------+------+--------+-----------+----------+------------+-------------+
|    1 | SIMPLE      | tabDelivery Note | index | NULL          | modified | 9       | NULL | 207015 | 348940.00 |   100.00 |       0.00 | Using where |
+------+-------------+------------------+-------+---------------+----------+---------+------+--------+-----------+----------+------------+-------------+
```

After

```
+------+-------------+------------------+------+-----------------+-----------------+---------+-------+------+--------+----------+------------+------------------------------->
| id   | select_type | table            | type | possible_keys   | key             | key_len | ref   | rows | r_rows | filtered | r_filtered | Extra                         >
+------+-------------+------------------+------+-----------------+-----------------+---------+-------+------+--------+----------+------------+------------------------------->
|    1 | SIMPLE      | tabDelivery Note | ref  | pick_list_index | pick_list_index | 563     | const | 1    | 0.00   |   100.00 |     100.00 | Using index condition; Using w>
+------+-------------+------------------+------+-----------------+-----------------+---------+-------+------+--------+----------+------------+------------------------------->
```

(cherry picked from commit 433489a)

# Conflicts:
#	erpnext/stock/doctype/delivery_note/delivery_note.json