SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cad58da976258261ea18135dae9dfd369571ea800f1d952d6438b7cd1567643b' 
  AND token = 'sWE+IkHZwB9bI6TyUAYJQzjyRHWUOvP5wvErN2nf2kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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