SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfe1deb5df80f6e86dd673cb99bf1427e9a047961593dbf5f0cb22561b41619b' 
  AND token = '0FeGQmgDiEPQaBMGOJRGcabh2zhtHVsGkP5wLsPVQcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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