SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb6efcd0cedf1067f3509eb594eef16c463fc53f98bb66f9e16e6bee59c987fe' 
  AND token = '2AjCATk6Jzwrf+369t0/ZV1YyXCLDwVtPNvY6wEx5RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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