SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2086, 2117, 2218, 2137, 2260, 2273, 2256, 
    2258, 2002, 2257, 2342, 1983, 2005, 
    2118, 2015, 2276, 2300, 1994, 2143, 
    2261, 2294, 2072, 3551, 2278, 2129, 
    2269, 2315, 1995, 2136, 2290, 2320, 
    2343
  ) 
  AND category_id != 414

Query time 0.00096

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "35.46"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 61,
      "rows_produced_per_join": 61,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_categories`.`parent_id` in (2086,2117,2218,2137,2260,2273,2256,2258,2002,2257,2342,1983,2005,2118,2015,2276,2300,1994,2143,2261,2294,2072,3551,2278,2129,2269,2315,1995,2136,2290,2320,2343))",
      "cost_info": {
        "read_cost": "29.36",
        "eval_cost": "6.10",
        "prefix_cost": "35.46",
        "data_read_per_join": "215K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`s2cart`.`cscart_categories`.`category_id` <> 414)"
    }
  }
}

Result

category_id parent_id
1996 1995
1997 1995
1998 1995
1999 1995
2000 1995
2001 1995
2003 2002
2004 2002
2006 2005
2087 2086
2088 2086
2089 2086
2090 2086
2091 2086
2130 2129
2131 2129
2132 2129
2133 2129
2134 2129
2135 2129
2138 2137
2139 2137
2144 2143
2145 2143
2146 2143
2147 2143
2148 2143
2149 2143
2150 2143
2151 2143
2152 2143
2153 2143
2154 2143
2259 2258
2270 2269
2271 2269
2272 2269
2279 2278
2280 2278
2281 2278
2344 2343