SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96adc9af232748633e2017f42e4831b447579dac842949f003b7b6f605a9ed70' 
  AND token = 'bfVE+bgqG8Ieyza2nWcsdAAr0i3PqwfBdKlhcBQSsTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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