SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34463aac2182d9928e7aa2dfcff684e9270ed0bc03d743c192f2b7330a61e2e5' 
  AND token = 'P9Y15l7fzA9oTPYsJ91P2v9kIMvOhyMkFwlqli5k/7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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