SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f71ab980c0bef64eb58782ab8023a028636d641a8ec4358957b997f04f53916' 
  AND token = 'OIYjWvcr1RrzF4yR7UhqLQPrcBZAIxz4PCM9/sO961Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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