$query = DB::table('postcode_records')->select('uuid', 'postcode', 'address', 'sale_date')->where('postcode', '=', $pcode)->get();

+--------------------+--------------+------+-----+---------+-------+
| Field              | Type         | Null | Key | Default | Extra |
+--------------------+--------------+------+-----+---------+-------+
| uuid               | varchar(250) | NO   | PRI | NULL    |       |
| sale_price         | int(10)      | NO   |     | NULL    |       |
| sale_date          | datetime     | NO   | PRI | NULL    |       |
| postcode           | varchar(15)  | NO   | PRI | NULL    |       |
| house_name_num     | varchar(50)  | NO   |     | NULL    |       |
| flat_or_apartment  | varchar(50)  | NO   |     | NULL    |       |
| street             | varchar(50)  | NO   |     | NULL    |       |
| town               | varchar(150) | NO   |     | NULL    |       |
| address            | varchar(150) | NO   |     | NULL    |       |
| city               | varchar(150) | NO   |     | NULL    |       |
| district           | varchar(152) | NO   |     | NULL    |       |
+--------------------+--------------+------+-----+---------+-------+

+--------------------+--------------+------+-----+---------+-------+
| Field              | Type         | Null | Key | Default | Extra |
+--------------------+--------------+------+-----+---------+-------+
| uuid               | varchar(250) | NO   | PRI | NULL    |       |
| sale_price         | int(10)      | NO   |     | NULL    |       |
| sale_date          | datetime     | NO   |     | NULL    |       |
| postcode           | varchar(15)  | NO   |     | NULL    |       |
| house_name_num     | varchar(50)  | NO   |     | NULL    |       |
| flat_or_apartment  | varchar(50)  | NO   |     | NULL    |       |
| street             | varchar(50)  | NO   |     | NULL    |       |
| town               | varchar(150) | NO   |     | NULL    |       |
| address            | varchar(150) | NO   |     | NULL    |       |
| city               | varchar(150) | NO   |     | NULL    |       |
| district           | varchar(152) | NO   |     | NULL    |       |
+--------------------+--------------+------+-----+---------+-------+

"000000D6-CFA4-476E-95A4-8680BE96B482","181995","2005-12-14 00:00:00","ST11 9TL","S","Y","F","12",,"HOFFMAN DRIVE","BLYTHE BRIDGE","STOKE-ON-TRENT","STAFFORD","STAFFORDSHIRE","A","A"
"000000FE-94CA-47DA-8D75-6FDFA5960D75","75000","2002-03-20 00:00:00","DA9 9PT","F","N","L","20",,"SWALLOW CLOSE","GREENHITHE","GREENHITHE","DARTFORD","KENT","A","A"
"0000012D-3A97-4FF7-BCA7-897FAA91E25B","52500","1997-06-27 00:00:00","BS20 6JQ","S","N","F","14",,"AVON WAY","PORTISHEAD","BRISTOL","NORTH SOMERSET","NORTH SOMERSET","A","A"

MariaDB [test]> explain select uuid, postcode, address, sale_date from postcode_records where postcode = 'BS20 6JQ';
+------+-------------+------------------+------+---------------+------+---------+------+-------+-------------+
| id   | select_type | table            | type | possible_keys | key  | key_len | ref  | rows  | Extra       |
+------+-------------+------------------+------+---------------+------+---------+------+-------+-------------+
|    1 | SIMPLE      | postcode_records | ALL  | NULL          | NULL | NULL    | NULL | xxxxx | Using where |
+------+-------------+------------------+------+---------------+------+---------+------+-------+-------------+

ALTER TABLE postcode_records DROP PRIMARY KEY;
ALTER TABLE postcode_records ADD PRIMARY KEY (postcode,uuid,sale_date);
ANALYZE TABLE postcode_records;

+------+-------------+------------------+------+---------------+---------+---------+-------+-------+-------------+
| id   | select_type | table            | type | possible_keys | key     | key_len | ref   | rows  | Extra       |
+------+-------------+------------------+------+---------------+---------+---------+-------+-------+-------------+
|    1 | SIMPLE      | postcode_records | ref  | PRIMARY       | PRIMARY | 17      | const | zzzzz | Using where |
+------+-------------+------------------+------+---------------+---------+---------+-------+-------+-------------+