SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c6273f83aec88dca94716cf215245ef411a0f7229ebea266d78b3f459859174' 
  AND token = 'sgl3Eki2UcvDrSLlIYSXEjJGDEYIHme9P42Bw1sKzV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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