SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '157523727d52278bf77243e526371ea6868421fe8b9a3dab46360b34ace5d16f' 
  AND token = 'GptcpMeA9OdyUt016ooRj45B3k8HoLKQdDIgQtKTeTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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