SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c8d3573174d74d10f88d0a0af33425e33a0f838b8564f7fadc96367f83921a8' 
  AND token = 'fLYprJkvEYr6Nq9n7nmQyjBSo/FPBPCLxWGgOyXWVKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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