SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f93910229830aceb8b53e2bfc0c8baa6ee5a5c55bed6926a2f8e16bf315644ad' 
  AND token = 'xiK5cu9HGkIXQbOUzJXgF0rXIha9/WCmQ70qlQvIGo8=' 
  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"
    }
  }
}