SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '661749f6189f08d1e3e463d8fa5a7c9abc2cb22bc5fc985930615361b07eab38' 
  AND token = 'X717j+NCqIkutnhQrTlUxMMZXTTY6CFMP5kfxtkKdVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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