SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '06df5ad61f981c2acf3ddc7dd476dd9835dcea9a9cc0c0539c64ecfb9dca6258' 
  AND token = 'nU415eoWP9NW8lOhUIK8+TuBPM1zY/Mb5HZYM16a17A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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