SELECT 
  id_path 
FROM 
  netting_categories 
WHERE 
  category_id IN (310, 318, 378, 466)

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "netting_categories",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "p_category_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["category_id"],
          "rows": 4,
          "filtered": 100,
          "index_condition": "netting_categories.category_id in (310,318,378,466)"
        }
      }
    ]
  }
}