SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '800fd5e86f40d41bdba6faf5db4bd226856e999dd9478be0f068a728ed731de4' 
  AND token = 'IPVfXfwL6aVoaRIhXZBOpXVyK7jcdss+qeB75aXOfXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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