SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36fca6ffc8984fc0d329b66ee44cad980a8154191b748f2c33f6bfb12945c862' 
  AND token = 'EUWNDL6wN/4HBupJKO0qAEpFAS7HqdzlvBe+f09uyls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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