SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43c6417eae10d8a5dd62b1cd13c706ed96235bab668b73477d8b17f493baf88b' 
  AND token = '/iFoWXPqZJo81Wwxn307aKSMibbLsc4ai7ydm9joRjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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