SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '126a3eafedd6b0ed5cd76b444da20ce49994f3b0a502124924ba9d94c4571742' 
  AND token = 'DHKUts9zzrMK8WUY/lTw2qot3jree54eQNk2uGoU/hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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