SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d3b9ebd8ac7fe36d91d0b93995f639f37b3a8ec0a4db1419559d1d6f2aff81' 
  AND token = '0bUJyu5L/ywuVaZZZQNjVN51Vf6B+eZyW6QYgqGpA5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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