SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3b80a544bb248e48fcf773de657ec982efbb18d4dc8d5425de3c49467d5ff26' 
  AND token = 'ZRN8Ho8BgqMqXzDDzK4Gwzb6r3PrwjSM34LBlQpUzqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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