SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c520df254810e82997f3b0e327f5cc29fde20655c418ff96999ed57d8e40df80' 
  AND token = 'G/KYSj0+uiOXaY7uZu2O0Z0eCcMs5WnOu3F/yxhLchI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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