SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e64f3d9e5ff21281a97efe9c0e0883e66949afeec45a64ce9cbedaefb1551dcd' 
  AND token = 'DyBcJps0DOHaiVFlL2TNi7nWN+06TRTHMUYWOWfERoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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