SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa3f43f6183ddf8817bc09b740217e8a5cb6d91076973c366f62868457c8cd65' 
  AND token = 'Wc7aLCjS5uJZ6ITxzq1925t7biJV2Ct14DlDt0steVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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