SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65c2cd42d23ae822fb3bcdd2ad821c56b4fe3c619e9f05e5b89c3a34d860bca6' 
  AND token = 'irBbHnwh3vWADdCiCrfQIGrqMxnKqprsUuXY8wVgIpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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