SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '728108683163c5810d685ea3a7a923185b916bfc0966ef02269fec95b5d71b78' 
  AND token = 'fjm/E9tvUs/8nQV+ZVuj6fd4SjbFe2gYL5AHLQEVj+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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