SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01a71c7ff10a9af36f08e518a8aefba000f1f4cba9a32acb775a35b2cfe59209' 
  AND token = '0e4wmxjNcyL4LJFcVmIB5nQkjnEnxe4Lt0vxSMs+ASI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}