SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9371fbcc1b69bbc0de5998128a8c272d1b76dadc35aed1ab84b39ca18789d36' 
  AND token = 'pNOfh+RFEz4xYBgoHgqGbUQPp72QGIvqP5CY7jqhHgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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