SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa462737bd719f0a6362826d8c33a81fbff8884f4f7ede7bbadaf2001fbb850b' 
  AND token = 'o2RaiA9gMe+O2UQpHgTF6gfGK7wdVkCgLIzvi+dPCz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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