SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '472e33e7f6da03455ac74a08341b98557fe3a423b519bdf5d130faf8af9bff92' 
  AND token = 'tQELNDuatfKzy8d0lNPk7EKOnIp19pz4UsqlggEytk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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