SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '416b186d03510af96584d6f0bc13ec6eacb56dfc7bb4a43b1326aa4605b01345' 
  AND token = '35JCOOPAe0e8+ZcP1zIGSGvRwKE0NrXTmFLuuvQNlJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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