SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '355511f1c8d3be1489bfa9a5d45d303c60cda72189cccfb1ddeb418dea7259ca' 
  AND token = 'OXRanrQhFa9PkPD7YnZ4NDUWpZ1DXVTrtATJc9jCqaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}