SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fdc580a8438510218f69ee3ab7769af593bed4457493132ee666c89452f7d42' 
  AND token = 'vYZzYfFYLSvTMJThlYazJFWqrOS8pNnYGecqmOWiIUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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