SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '70d368017332ed9c637acf8ff75c41a5ccb30651012a43456d759d3d88e58251' 
  AND token = 'iJU1kKkbySCERwx/yrej/rr/zHoTDilRxeqq7TKM/LA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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