SELECT 
  cscart_users.* 
FROM 
  cscart_users 
WHERE 
  user_id = 80

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_users",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["user_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    }
  }
}

Result

user_id status user_type user_login referer is_root company_id last_login last_activity timestamp password salt firstname lastname company email phone fax url tax_exempt lang_code birthday purchase_timestamp_from purchase_timestamp_to responsible_email password_change_timestamp api_key helpdesk_user_id storefront_id janrain_identifier
80 A V user_80 Y 18 1773238972 1773247766 1721581132 $2y$10$K1CS13VVm9RkFqPTOYpBU.EMmIqrKqRSK69SNEO35sf3Z64883YLW FastGold encrypticxls@protonmail.com N en 0 0 0 1721581132 0 0