SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dede56042ec968782f410b670755e22e05cd705821809e7c64fe08f15aca10d4' 
  AND token = '3IdPlffHMJxkbxWQFd7ll0xujwHdZCAelbnKOiz7HuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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