SELECT 
  SQL_CALC_FOUND_ROWS cscart_cp_blog_posts.post_id 
FROM 
  cscart_cp_blog_posts 
  INNER JOIN cscart_cp_blog_post_categories ON cscart_cp_blog_post_categories.post_id = cscart_cp_blog_posts.post_id 
  INNER JOIN cscart_cp_blog_categories ON cscart_cp_blog_categories.category_id = cscart_cp_blog_post_categories.category_id 
  AND (
    cscart_cp_blog_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_cp_blog_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_cp_blog_categories.usergroup_ids
    )
  ) 
  AND cscart_cp_blog_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_cp_blog_post_descriptions ON cscart_cp_blog_posts.post_id = cscart_cp_blog_post_descriptions.post_id 
  AND cscart_cp_blog_post_descriptions.lang_code = 'ru' 
  LEFT JOIN cscart_cp_blog_authors ON cscart_cp_blog_authors.author_id = cscart_cp_blog_posts.author_id 
WHERE 
  1 
  AND cscart_cp_blog_posts.status IN ('A') 
  AND cscart_cp_blog_categories.company_id = 1 
  AND (
    cscart_cp_blog_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_cp_blog_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_cp_blog_categories.usergroup_ids
    )
  ) 
  AND (
    cscart_cp_blog_posts.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_cp_blog_posts.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_cp_blog_posts.usergroup_ids
    )
  ) 
  AND (
    cscart_cp_blog_posts.use_avail_period = 'N' 
    OR (
      cscart_cp_blog_posts.use_avail_period = 'Y' 
      AND cscart_cp_blog_posts.avail_from_timestamp <= 1771127366 
      AND cscart_cp_blog_posts.avail_till_timestamp >= 1771127366
    )
  ) 
  AND cscart_cp_blog_post_categories.category_id IN (7) 
GROUP BY 
  cscart_cp_blog_posts.post_id 
ORDER BY 
  cscart_cp_blog_posts.timestamp desc, 
  cscart_cp_blog_posts.post_id desc 
LIMIT 
  0, 12

Query time 0.00076

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_cp_blog_posts.`timestamp` desc, cscart_cp_blog_posts.post_id desc",
      "temporary_table": {
        "table": {
          "table_name": "cscart_cp_blog_authors",
          "access_type": "system",
          "possible_keys": ["PRIMARY"],
          "rows": 0,
          "filtered": 0,
          "const_row_not_found": true
        },
        "table": {
          "table_name": "cscart_cp_blog_categories",
          "access_type": "const",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["category_id"],
          "ref": ["const"],
          "rows": 1,
          "filtered": 100
        },
        "table": {
          "table_name": "cscart_cp_blog_posts",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY", "status"],
          "rows": 18,
          "filtered": 94.44444275,
          "attached_condition": "cscart_cp_blog_posts.`status` = 'A' and (cscart_cp_blog_posts.usergroup_ids = '' or find_in_set(0,cscart_cp_blog_posts.usergroup_ids) or find_in_set(1,cscart_cp_blog_posts.usergroup_ids)) and (cscart_cp_blog_posts.use_avail_period = 'N' or cscart_cp_blog_posts.use_avail_period = 'Y' and cscart_cp_blog_posts.avail_from_timestamp <= 1771127366 and cscart_cp_blog_posts.avail_till_timestamp >= 1771127366)"
        },
        "table": {
          "table_name": "cscart_cp_blog_post_categories",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "6",
          "used_key_parts": ["post_id", "category_id"],
          "ref": ["noframes_kz_new.cscart_cp_blog_posts.post_id", "const"],
          "rows": 1,
          "filtered": 100,
          "using_index": true
        }
      }
    }
  }
}