SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84f76e8c5613c01918f477f319871507c5f79a20c51aaf05145b6cef24c8647c' 
  AND token = '/z4bQQECwYfWYikT22birtk5UemMrj8OZu37ubswKzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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