SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f553988191b2c9ad423a1019baf521305de275084011985506a85e34c684d0f' 
  AND token = 'pBSjnXzLpBegTGCypKcICpI/zNSoP+7xai4LYpQMXtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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