SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d9f859436f921727dc3aae9c8e022fbf948565a57700211f1b42143f9735672' 
  AND token = 'YMSpILMturgEkvFAcRw1mjaFRogC/VHIDo9nClhgN4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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