SELECT 
  *, 
  IFNULL(
    ab__emd_cp.category_pattern_id, 
    0
  ) as ab__emd__category_pattern_id, 
  IFNULL(
    ab__emd_cp.products_pattern_id, 
    0
  ) as ab__emd__products_pattern_id 
FROM 
  cscart_categories 
  LEFT JOIN cscart_category_descriptions ON cscart_category_descriptions.category_id = cscart_categories.category_id 
  AND cscart_category_descriptions.lang_code = 'en' 
  LEFT JOIN cscart_ab__emd_categories_patterns AS ab__emd_cp ON ab__emd_cp.category_id = cscart_categories.category_id 
WHERE 
  cscart_categories.category_id = 201 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  )

Query time 0.00092

JSON explain

{
  "query_block": {
    "select_id": 1,
    "const_condition": "1",
    "table": {
      "table_name": "cscart_categories",
      "access_type": "const",
      "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "cscart_category_descriptions",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["category_id", "lang_code"],
      "ref": ["const", "const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "ab__emd_cp",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "ref": ["const"],
      "rows": 0,
      "filtered": 0,
      "unique_row_not_found": true
    }
  }
}