SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1292881769316f1705e426836e6632c0f0cdf15d28edb96072ba28cb062d111' 
  AND token = 'F6k8280vkMdPL68OTM0DkhCTmuXlNn3QSMW6nLXkr6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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