Postgres Query running slow, using pgcrypto extension in postgres sql

Question

I am facing issue while using the django-pgcrypto-fields. Model has charsymmetricfield and emailsymmetricfield.

using pgcrypto externsion in postgres sql, following is the output for below queries

Query 1:

explain analyze (select * from table_name);  

above query taking time around 900 ms

but when i am using query with 'pgp_sym_decrypt' it taking longer time around 54 sec, that is too high

Encrypted column is indexed

explain analyze (select
    pgp_sym_decrypt("table_name"."sender_contact_person_name",
    'encryption_key')::text,
    pgp_sym_decrypt("table_name"."sender_contact_person_email", 'encryption_key')::text,
    pgp_sym_decrypt("table_name"."sender_contact_person_contact_no",
    'encryption_key')::text,
    pgp_sym_decrypt("table_name"."recipient_contact_person_name",
    'encryption_key')::text,
    pgp_sym_decrypt("table_name"."recipient_contact_person_email",
    'encryption_key')::text,
    pgp_sym_decrypt("table_name"."recipient_contact_person_contact_no",
    'encryption_key')::text,
from
    "table_name"
where
    "table_name"."is_active"
order by
    "table_name"."pickup_date_time"
limit 10)

To add Pgcrypto in system i follow below steps

• added pgcrypto extension in postgres sql
• added pgcrypto in INSTALLED_APP in base settings.
• added django-pgcrypto-fields plug in.
• replace model char fields to charpgpsymmetric fields.
• copy data in encrypted format in encrypted fields.

Any input will be very helpful, as system is very slow.

expecting query execution time to be minimum