What should be the MySQL query execution time?

Question

PHP

Hello, help optimize the request to reduce the response time.
In general, there is a request for a selection of publications for a news feed similar to VK.
At the same time, there are categories and cities that the user can select.
One publication can be in several cities and in several categories.
And the last difficulty, there are categories and cities that can only be viewed by subscribers.
The structure is:
Publication:
id
--many fields--
Sities:
id
name
Categories:
id
name
Pub_kat
id
kat_id
pub_id
Pub_sity
id
sity_id
pub_id
In php I generate variables:

//выбранные категории, вернет строку типа - "1,2,3" исключая недоступные для юсера
$true_kat;
//выбранные города, вернет строку типа - "1,2,3" исключая недоступные для юсера
$true_sity;

//запрещенные для юсера категории, если он подписчик или их нет то вернет 0
$false_kat;
//запрещенные для юсера города, если он подписчик или их нет то вернет 0
$false_sity;

The request itself, with a little addition, to get likes and dislikes for publications

SELECT c.id, c.text, c.date, c.name,
(SELECT count(liked) FROM Likes_pub
 WHERE liked = 1 and pub_id=c.id) as 'like',
(SELECT count(liked) FROM Likes_pub
 WHERE liked = 0 and pub_id=c.id) as 'dislike'
FROM Publication c
WHERE c.id in 
(SELECT pub_id FROM Pub_kat WHERE kat_id in ($true_kat) and pub_id in
(SELECT pub_id FROM Pub_sity WHERE sity_id in ($true_sity))) 
AND
c.id not in 
(SELECT pub_id FROM Pub_kat WHERE kat_id in ($false_kat) and pub_id not in
(SELECT pub_id FROM Pub_sity WHERE sity_id in ($false_sity)))
ORDER by c.id DESC LIMIT 0,20

Without extra:

SELECT c.name
FROM Publication c
WHERE c.id in 
(SELECT pub_id FROM Pub_kat WHERE kat_id in ($true_kat) and pub_id in
(SELECT pub_id FROM Pub_sity WHERE sity_id in ($true_sity))) 
AND
c.id not in 
(SELECT pub_id FROM Pub_kat WHERE kat_id in ($false_kat) and pub_id not in
(SELECT pub_id FROM Pub_sity WHERE sity_id in ($false_sity)))
ORDER by c.id DESC LIMIT 0,20

In general, this request, on local hosting, takes 2.6 seconds, I somehow wrote something instead of variables, it took 8 seconds in general. On a hosting it will be even worse.
I feel that it shouldn't be like this, but it doesn't occur to me how to optimize.
I will be glad to any advice)
Thanks in advance for the answer.

Answer 1

explain

Answer 2

I do not have in-depth knowledge of subd. Once I also made such nested queries, exactly the same ...IN(SELECT id... For some reason, I intuitively decided that it would be faster than making separate queries. And then I stumbled upon these brakes. For the experiment, I tried to make nested queries with different queries and then form the main one.It turned out to be faster than 400 times