SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bae92b0721b3b23d9b31e4a9742268633bc46235a7feccd07821d338d51caf0' 
  AND token = 'BrKyq2BvI96+HQHLBF1YWCR1vntcXHy2vL+VAqSFRkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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