SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cf3b690f656f52a0068347fc696994d570fff9a6bae7fb7455931c778652347' 
  AND token = 'lVChMhDbueYeWVlpyjEuHKTHf9VKuu7CTFDl3i2p+7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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