SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b263161612382b0ef21d3c7c97cc026d7d8e9d346ca3c2a2364827533e99484d' 
  AND token = 'W05nl7x2q+M20Da81fMlmcq/YOHY17yu2V+o4guOafc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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