SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6983d7b81bfad11c87d42c998ba43fecf5a214474609c4fc6cd75c8be9d489a9' 
  AND token = 'XWwaBT80vTLrySdUYwMqcTfp8n0kYbUrFggKnHYIFd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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