SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b43910a6f2b5ce12b78dbd21f4fc0dcdcb395c36b2efd243d4081b41ba3c44e9' 
  AND token = 'BeJhF3z6Kq3GebRlkmvAip2BMwGpaVwLUCFnfAP0w+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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