SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b38c8fdfefb89746f0ca0269ecf1f27b3fb8f280bedffdf1f181320f4a59de4' 
  AND token = 'cl2YXTTVgZkAnCFWpyaxu75Jvi5naIglEyLZB6qVxTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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