SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbc2c7155912294b9be0ee07923f75edc875f771fcdc2e6769eb227fabd0d454' 
  AND token = 'GTzMy/mDJm63bhTBuIAlq50ah+MQPEFjM/QHStbNH1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}