Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df6a76eed416629df19e0bf5095098ff56a3b814473d2b11f5e0456ac1ba250f' 
  AND token = 'h7njYbp2Otoo2Olj1EZ9HAHP9YnfNPuh/bMaFRoMtgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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