SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df7ba396ac54d31d324f569680790e5eafe7207d3999cb23c08878d3c5fec5a8' 
  AND token = 'lEzIYoeYtRs8pZtWp/XA6+VfxXVj7+7hM+BmeluYdHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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