SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8335c59c646fe3e794fae1b656a84d1370cb86c31873cc279b109868ff663467' 
  AND token = '5hsKxXAUx6J/+XETtdZHPvl6vbjcnlzGRmEC43mP5DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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