SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bce54c2d2c203f198a36a8cb7bb19159f367c8e997ba468a0dee973d682ec2ad' 
  AND token = 'K4TMIAg/wFFS9IhfKo0+lCzYXjuZ2m5AEDbuKnlhz4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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