SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92104cf7a628ebb0f77b98ea21878a88bed6eed9dbf42c54aa44bd4ea629bbca' 
  AND token = 'RpkPXPDjYiIy3HjFoVIYX7HOcGcWr3cnAjMi99XTI78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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