PostgreSQL query with If condition

I am trying to fetch records based on below conditions.
Lets take today's date is 2018-01-23
Condition 1: Fetch the records having date_col_1 >= today-1
Condition 2: If date_col_1 > today then date_col_2 > today
Queries

create table order_tbl(order_id integer primary key,
                  date_col_1 timestamp with time zone,
                  date_col_2 timestamp with time zone);
insert into order_tbl values (1, '2018-01-21', '2018-01-25');
insert into order_tbl values (2, '2018-01-22', '2018-01-25');
insert into order_tbl values (3, '2018-01-21', '2018-01-22');
insert into order_tbl values (4, '2018-01-23', '2018-01-25');
insert into order_tbl values (5, '2018-01-24', '2018-01-24');
insert into order_tbl values (6, '2018-01-21', '2018-01-23');
insert into order_tbl values (7, '2018-01-25', '2018-01-22');
insert into order_tbl values (8, '2018-01-26', '2018-01-26');

How to achieve IF condition in WHERE clause in PostgreSQL.