SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcd1be79f89137b8887597ec4d2e7660363b4f6c262a5fa37573d8654e5734d5' 
  AND token = 'QSJ2HI6pZRT67jP1ladVgOJy5zjc604LJFSKKwV/ZFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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