SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4ff9d9cb8afad25de02ad91fb6df5d5769d7ee6d4da9885cbc1b31645566badb' 
  AND token = 'UG1m576cmbFXKBRfLfePsFl1blFathnw0m/XZkC4pRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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