SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd7ba9b90214e51c30150b54ba0379b439e308bee6e18e98fc2c1eff1a1af8ac' 
  AND token = '8h6VmDGEas/hOY9Ui4lU1iYuhujAkXqrzK0hm+Wq1xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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