SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65b966de07c63020ca1638c87d0e103845396629993ea52a58122caced331c2b' 
  AND token = 'PdEYHr6ruYB2v3EmQrEo2tqROaz9RgqakhYqKQycnLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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