SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb18511c4d4f0429adaa3d8e63e1fb1e613d575c2967820f5d3b275f33189a61' 
  AND token = 'KPTU0Rd9ZDo0gpZtPrlMB0vnjaHiqdOQg/eCzLeP5Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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