PostgreSQL inherited child tables indexes make select slow

Question

I Have one parent table hotels. These table have 2 child tables:

CREATE TABLE IF NOT EXISTS hotels_active (
    CHECK (status_text = 'ACTIVE'),
    LIKE hotels INCLUDING ALL
    ) INHERITS (hotels);

CREATE TABLE IF NOT EXISTS hotels_inactive (
    CHECK (status_text <> 'INACTIVE'),
    LIKE hotels INCLUDING ALL 
    ) INHERITS (hotels);

After that I create even more child tables based on USA states:

DECLARE
    i text; 
BEGIN 
    FOR i IN (SELECT unnest(enum_range(NULL::hotelsdata.StateE))) LOOP 
        EXECUTE 'CREATE TABLE IF NOT EXISTS hotels_active_state_' || i || ' (
            CHECK (state = ''' || i || '''),
            LIKE hotels_active INCLUDING ALL
            ) INHERITS (hotels_active);
        ;';

        EXECUTE 'CREATE TABLE IF NOT EXISTS hotels_inactive_state_' || i || ' (
            CHECK (state = ''' || i || '''),
            LIKE hotels_inactive INCLUDING ALL
            ) INHERITS (hotels_inactive);
        ;';

    END LOOP;
END;

I also have indexes on parent hotel table that are inherited to child state tables when we write: LIKE hotels INCLUDING ALL

CREATE INDEX IF NOT EXISTS hotels_column_1_index ON hotels (column_1);
CREATE INDEX IF NOT EXISTS hotels_column_2_index ON hotels (column_2);
CREATE INDEX IF NOT EXISTS hotels_column_3_index ON hotels (column_3);
CREATE INDEX IF NOT EXISTS hotels_column_4_index ON hotels (column_4);

Everything works fine and indexes work too, but when I have any more than 4 indexes for any columns, query planning time goes from 10ms to 700ms. It works well with less than 5 indexes for any columns. So what can be a problem? why changing number of indexes from 4 to 5 have such a bad effect?

Query is simple like that: SELECT hotels.name FROM hotels WHERE hotels.state = 'AZ';