SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '589a8afeb0305d0edfc5e45f8bb7858f8a85de23a68e5fec21f27810f00e1520' 
  AND token = 'T0tr+0HGr0zpPUndaN6xTwTwRzWdZPci3mGYV3MhKtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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