SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fed5b2645991398054ab39fec1aed72f994679a7d8384c466c98e01862f8224d' 
  AND token = 'KfHvSIy1pYoaDjPuPzmcYNVdoylmsE3C+wh+Zk85ax0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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