SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1892b645d6d8e2956e7fdf67ebc400983e53cea74329254d77d833b016f83540' 
  AND token = 'raUn8mi0OSRRPq5pWIq9qFrtT9JENSQA4J4VusOITCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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