SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17bb10e4baa5bab0c1d916c649b55838f8f8e3ba584d24f6c941146a8650642f' 
  AND token = 'FGKt9qwUTnV41z9Q9W3cPLJq1lIvaCx/jrTZYCwEQ0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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