SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d1faf1b644a1eee587fa485ff3004c69b13831c867540528d5743781af25c76' 
  AND token = 'hEjE5SmKXksQuLwwAEC3jsq7HAk8Q3FRa+vckw0K3Rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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