SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '238f533e49e67b564b064567229333f2db4dc48dae614cfe7015a627d3df8bc5' 
  AND token = 'RiLfWhfGb3C1jvFjK/V/CKCaBdnRGc2GJ9j2BtQGGOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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