SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e7ba3dcd9bc2ee84dabb96f5bb265fc1daf58f4dc3b7cb8f665c059b76b4949' 
  AND token = 'RJxRAQOWo6UffZbx8eYHG5MstuOwhimehjjSP6PHc1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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