SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2017f420a229de7827d093c79391625e58d5134f476cadfca939459d0f0ea38' 
  AND token = 'olraxP2TIU3h5EzkYJJGiAYXkhYFdy5jwFAhl2XtWMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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