SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3636b96bd885c5612c58c532e737b9599f7939cb6052ee145e9995bd6cad1dbb' 
  AND token = 'TM3jmqagxSNfRBHbcJ1KHioT+k1xKqtnaHhPW4uWx+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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