SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a1ee810063af4f941234a6daddbd6b0221515cabbed16371b06ebf2d8e7ff46' 
  AND token = 'QB9e2+nvjr16uAwlHxwk2wbKPgVYlIMcRnZOPLap+RY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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