SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a587e95cb1eeb55fffeaf25a12eb7207ddbb283724a3b58288fff88af73f5ebe' 
  AND token = 'JohO0Boz68fOihALtBt5Ylnww7EXD8gO44p+tlM9kvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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