SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7396de3af3c92dd588f78864918631be7558ab6cd052e40717ae91b20feb5776' 
  AND token = 'cDlH9I66vkoR9IOQRGHC+BLppMQcOAIdzXVic2OLU5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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